Section 1
The five challenges at a glance
Marn and Rosiello observed that transaction pricing is 'won or lost in hundreds, sometimes thousands, of individual decisions each day', and that money leaks away from list price through discounts, incentives, and giveaways nobody tracks in aggregate (McKinsey, 2003). In an agency, those decisions are made by account managers approving 'one quick extra deliverable,' creative leads granting a fourth revision round, and founders accepting net-60 terms to close a deal. Each decision looks trivially small. The waterfall's power is forcing all of them onto a single chart, from quoted fee to pocket price, so the cumulative erosion becomes visible. The table below summarizes the five leaks that dominate service-business waterfalls, their root causes, and the evidence base for each. Most firms that run this exercise for the first time discover their pocket price sits 15-25% below their quoted fee, and that the spread between their best-realized and worst-realized clients (what Marn and Rosiello call the pocket price band) is wider still. That band is where the recovery opportunity lives: the goal is not to fire low-pocket-price clients overnight but to understand exactly which concessions created the gap and reprice or renegotiate them deliberately.
Section 2
Challenge 1: Scope leaks are unpriced work, not goodwill
The Project Management Institute's Pulse of the Profession found that 52% of projects completed in the prior 12 months experienced scope creep or uncontrolled changes, up from 43% five years earlier (PMI, 2018). In product businesses, the waterfall's biggest leaks are rebates and freight; in service businesses, the equivalent is unpriced labor delivered after the SOW is signed. Every 'small addition' a client requests and a team absorbs is functionally an off-invoice discount: the fee stays constant while the cost base grows, so pocket margin falls even though no discount appears on any document. This is why scope leakage is invisible in most agency P&Ls, it shows up as eroding delivery margin or sagging utilization, and gets misdiagnosed as a productivity problem rather than a pricing problem. Marn and Rosiello's insight applies directly: management attention focuses on list price (the quoted fee) while the real action is in transaction-level erosion (Marn and Rosiello, HBR, 1992). The fix starts with measurement. Pick your ten largest engagements from the last year and reconstruct the true delivered scope versus the contracted scope, priced at your standard rates. The gap, expressed as a percentage of contracted fee, is your scope-leak line on the waterfall. Firms running this audit typically find leakage of 10-20% on fixed-fee work, which, given the 11.1% profit leverage of 1% of price, usually exceeds their entire annual profit improvement target.
Section 3
Challenge 2: Free revisions and overservicing as off-invoice discounts
Marn and Rosiello distinguished between on-invoice discounts (visible on the bill) and off-invoice leakage, payment terms, co-op allowances, freight, that never appear on the invoice but reduce what the seller pockets (Marn and Rosiello, HBR, 1992). The service-business analog of off-invoice leakage is the revision round and the overserviced retainer. When a contract specifies two revision rounds and the team delivers five, those three extra rounds are real cost with zero associated revenue. When a retainer specifies 40 hours monthly and the team logs 55 to 'keep the client happy,' the effective realized rate has dropped 27%, without anyone approving a discount. SPI Research's vendor benchmark of 403 professional service firms found billable utilization fell to 68.9% in 2024, well below the 75% threshold the firm considers healthy (SPI Research, 2025, vendor data), and unbilled, overserviced hours are a major contributor. The discipline that fixes this is the same one McKinsey prescribes for product companies: make the leakage visible per account, then manage it. Track delivered-versus-contracted hours by client monthly. Convert the gap into currency at standard rates. Rank clients by effective realized rate rather than by headline fee. The ranking almost always surprises founders: some of the largest, most prestigious accounts sit at the bottom of the pocket price band, subsidized by smaller clients who pay closer to list.
Section 4
Challenge 3: Payment terms quietly reprice the deal
In the original waterfall, cash discounts for early payment and the cost of carrying receivables are explicit elements between invoice price and pocket price (Marn and Rosiello, HBR, 1992). Service founders routinely ignore this element when negotiating, treating net-60 or net-90 terms as a contractual formality rather than a price concession. The arithmetic says otherwise. If your firm's effective cost of capital or credit line runs 10-12% annually, agreeing to net-90 instead of net-15 on a large engagement hands the client roughly 2-2.5% of the fee in financing, a discount that never appears in any pricing discussion. Add late payment on top (enterprise clients routinely stretch stated terms) and the drag compounds. Simon-Kucher's vendor research on price realization shows the broader pattern: companies on average realize only 28% of their planned price increases, because concessions granted at the transaction level swallow the headline change (Simon-Kucher, 2023, vendor data). Payment terms are one of the most common swallowing mechanisms because procurement teams are trained to extract them precisely when the seller has stopped negotiating. The countermeasure is to price terms explicitly: publish a standard (for instance, 50% upfront, net-15 on balance), attach a stated cost to deviations (net-60 carries a 2% uplift), and offer a small, deliberate early-payment discount only where the cash conversion genuinely justifies it.
Section 5
Innovative solutions
The most effective modern responses borrow McKinsey's transaction-pricing discipline and adapt it to service delivery. First, build the agency waterfall as a standing report, not a one-off audit: quoted fee, negotiated discount, scope additions at standard rates, revision overage, overserviced hours, payment-term cost, and pocket price, per client, per quarter. Modern PSA and time-tracking platforms make this a configuration exercise rather than a data science project. Second, install a lightweight deal desk. McKinsey's pricing-governance research recommends approval workflows and deal desks so that discretionary discounts above a threshold require a second pair of eyes (McKinsey, 2021). For a 20-person agency this can be a single rule: any concession beyond 10%, in fee, scope, or terms, requires founder sign-off with a written reason logged. The log itself becomes pricing intelligence. Third, productize the leak points. Revisions become priced packs (two included, additional rounds at a published rate); rush delivery becomes a stated 25% premium; extended payment terms become a financed option with the cost visible. Each conversion turns an invisible concession into a visible, chargeable line. Fourth, reprice the pocket price band annually: identify the bottom decile of clients by realized rate and either renegotiate, restructure scope, or plan a respectful exit. Marn and Rosiello found that simply narrowing the band, bringing the worst transactions toward the average, delivered most of the profit gain.
Section 6
Solution framework
Use a five-step waterfall discipline, run quarterly. Step one: reconstruct. For every active engagement, chart the full waterfall from rate-card fee to pocket price, including scope additions valued at standard rates, revision and overservice hours, negotiated discounts, and payment-term cost. Step two: band. Plot all clients by pocket price as a percentage of list. Marn and Rosiello's pocket price band typically reveals a 2-4x spread between best and worst realized prices within the same firm (Marn and Rosiello, HBR, 1992); agencies show the same pattern in realized hourly rates. Step three: diagnose. For each bottom-quartile client, identify which waterfall element caused the erosion, the remedy for scope leakage (change-order discipline) is completely different from the remedy for term drag (repriced terms) or discounting (approval workflow). Step four: intervene. Sequence interventions by effort-to-impact: change-order enforcement and revision caps are contract-language fixes available at next renewal; discount governance is an internal policy available immediately; client exits are a last resort. Step five: institutionalize. Assign waterfall ownership to one person, review the report in the monthly leadership meeting, and tie account-manager incentives to realized rate rather than booked revenue. The shift in incentive basis matters most: PMI's research shows organizations with mature controls cut scope creep to 28% of projects versus 52% baseline (PMI, 2018), and control maturity follows whatever metric leadership actually inspects.
Section 7
Evidence-based action plan
Days 1-30: run the diagnostic. Pull your ten largest engagements from the trailing twelve months and build a waterfall for each: contracted fee, delivered scope at standard rates, revision and overservice hours, discounts granted, and payment-term cost at your cost of capital. Calculate pocket price and effective realized hourly rate per client. Expect to find a 15-25% gap between quoted and pocket price, consistent with the transaction-level leakage McKinsey documents across industries (McKinsey, 2003). Days 31-60: fix the contracts and the governance. Rewrite your SOW template with explicit deliverable counts, two included revision rounds with published overage rates, a change-order clause requiring written approval for additions, and standard payment terms with priced deviations. Install the single-rule deal desk: concessions over 10% need founder sign-off and a logged reason. Days 61-90: reprice the band. Take the bottom quartile of clients by realized rate into structured conversations at renewal: present the delivered-versus-contracted gap factually, propose either a fee adjustment or a scope reset, and hold the line, the 11.1% operating-profit leverage of each realized point (Marn and Rosiello, HBR, 1992) is the business case for tolerating the occasional difficult conversation. From day 91 onward, run the waterfall quarterly and track one headline metric: firm-wide pocket price as a percentage of list. Moving it three points is typically worth more than a year of new-business wins. For adjacent evidence in this pillar, see [Pricing New Services: What the Evidence Says About Penetration, Skimming, and Launch Price](/blog/growth-pricing-new-services-launch) and [Currency and Cross-Border Pricing for Service Firms: Purchasing Power, FX Risk, and Invoicing](/blog/growth-cross-border-currency-pricing).