Booking and billing are two different moments in the same deal: a booking is the signed commitment, a billing is the invoice raised against it, and collection is the cash arriving later still. A commission plan has to name which of the three triggers payment, because the same contract pays at three different times.
Commission is paid on closed business. That sentence sits in a great many plan documents, it reads as finished, and it names none of the three moments it could mean. A contract signed on 27 March, an invoice raised against it on 1 April, and a payment landing on 16 May are all defensible answers to when the deal happened, and the first quarter boundary to fall between two of them turns the ambiguity into an argument with a rep.
Each trigger buys something and costs something. Paying on booking gets money to the rep while the win still feels like a win, which is most of what makes a plan motivating, and it puts the company at risk for every deal that gets cancelled, disputed or never paid. Paying on collection eliminates that risk entirely and replaces it with a rep who cannot tell you what they will earn this quarter. Paying on billing sits in between and tracks the finance team's own recognition, which makes reconciliation far easier and stretches a twelve-month contract's commission across twelve months of pay runs.
Revenue-backed businesses with long collection cycles, agencies and anyone reselling third-party services tend toward billing or collection. Software companies with reliable customers tend toward booking, with a clawback clause covering the small tail of deals that fall over. The choice is a risk transfer, and it is worth deciding it deliberately rather than inheriting it from whichever field the first pay run happened to read.
A $90,000 twelve-month contract is signed on 27 March and invoiced quarterly. Each invoice settles 45 days after it is raised. Commission is 6% of contract value, which is $5,400 however it is delivered.
The annual cost to the company is identical under all three. What changes is the rep's cash flow, the size of the accrual finance carries, and how much a rep forfeits by resigning in October.
The plan document says commission is earned on booking. The data pipeline was built by someone who wired it to the invoice table, because that is where finance keeps revenue. Both are running. The deal pays once at signature and again at first invoice, and because the two records carry different identifiers, no duplicate check catches it. This is the single most expensive version of the booking and billing confusion, and it usually surfaces months later during an annual reconciliation, at which point recovering the overpayment is a conversation nobody wants to have. Name the trigger in the plan document and point the calculation at one field.
The long form lives in the guides: Clawbacks.
Commish pays booking vs billing the way your plan describes it, shows the arithmetic on every line, and traces each payment back to the deal that earned it.