Why did you pick the expensive courier? An honest answer, zone by zone

Priya Raman, Harvestline Grocery’s finance lead, flagged one line on the monthly invoice: 37.9% of orders route to FleetX, the priciest provider on the account. Provider means courier — the company that actually drives the package; the platform owns no vehicles and hands every order to one of them. Fair question — and this case answers it with arithmetic, not defense. Nothing is broken; a customer is asking us to justify our own routing with their money.

The honest answer splits. In part of the city the premium is buying something the invoice cannot see; in the rest it is a config decision nobody re-checked. The case keeps those two separate, because blending them would flatter us and cost the customer money.

Before any arithmetic, the receipts from the router — the automatic step that reads every courier’s offer and picks one — with one order per zone (a zone is one ZIP code; cost and reliability change street by street), showing every quote it saw at dispatch time. A quote is a courier’s answer when asked to take a job: a price and an estimated time. The router’s score is that price plus an expected-lateness cost built from each provider’s trailing on-time — how often it actually hit the promise in that ZIP over the past 30 days (A4). Cheap and unreliable loses to expensive and reliable downtown. And in the third panel, watch the quote that clears the reliability floor at a lower price and still loses. That is not a score. That is a pin — a manual override forcing one courier for a ZIP, whatever the scoring would pick.

The arithmetic, zone by zone. For each zone: what FleetX costs, what each alternative would save on the invoice, and what that saving costs back in refunds, support contacts, and SLA credits — money handed back when the on-time promise written into the contract (the SLA) is missed. The economics are illustrative (A7/A14) and every constant is printed below the tables:

Two mechanisms produce the 37.9%, and they deserve opposite treatment.

Merit. In 78701 and 78704, scored routing picks FleetX because every cheaper provider’s trailing on-time in those ZIPs sits far below it — the cheapest quotes downtown come from a provider running 74.3% on-time against FleetX’s 96.8%. Even the best alternative projects those zones to 85.6% and 86.1% — both through the 95% SLA floor. The router is doing its job.

Config debt — an old setting nobody turned off. In 78757 and 78759, FleetX is not winning a score — it is pinned. The pin dates to a February decision after a bad DashNow week, and nobody revisited it. Today Parcelet runs 95.7% and 96.1% trailing on-time in those ZIPs, and the pin just burns money — $10,808 a month of premium that is not justified.

Prevention is a calendar rule, not a dashboard: routing pins now carry a quarterly review and expire unless re-justified with current numbers. A pin is a bet that the router is wrong; the February bet was right for a week and wrong for a quarter. The query below is the standing check — zones where we dispatch above the cheapest quote even though the cheapest provider is clearing the reliability floor.