83 bookings a week at £10.79, reported in commission profit rather than gross

This client runs a marketplace. When a customer books, the business does not keep the booking value, it keeps a commission on it. That single fact changes what every advertising number means: a booking worth £89 gross is worth roughly a fifth of that to the business, and an acquisition cost that looks comfortable against the gross figure can be underwater against the real one.

Most reporting in this category quietly uses gross booking value, because it is the bigger number and it is what the ad platform hands you by default. It also makes it impossible to tell whether growth is profitable.

Every number reported to this client is commission profit, never gross booking value. We hold an explicit capture ratio for the account and apply it before anything reaches a report. The acquisition ceiling is then set against the real per-booking profit, with a lower alert line for the season when average booking values are known to fall.

We also documented, in writing and with the client's knowledge, a real limitation in the tracking: the platform's purchase event fires for two different products on this site, so a campaign focused on one of them will show some conversions belonging to the other. We chose not to hide this and not to over-correct it. Aggregate numbers are reported without a caveat because the contamination washes out at that level; campaign-specific numbers carry a short factual footnote; and we never scale the affected campaign on its own standalone return figure, using an independent payment-side source for clean counts instead.

Budget moves on this account are deliberately incremental, in roughly 10% steps against an agreed weekly booking target, rather than large jumps. Seasonal drops in average booking value are expected and explicitly excluded from anomaly alerts, so a normal summer pattern does not generate a false emergency.

At time of measurement the account was producing 83+ bookings a week at a £10.79 cost per booking, against a £14 acquisition ceiling, with commission profit per booking at £17, up from £14 a year earlier.

The honest framing: the cost-per-booking figure is only meaningful because it sits below a profit floor that was calculated from what the business actually keeps. The same £10.79 against a gross-value assumption would have told nobody anything.