A true-up is a correcting commission payment made after the fact, once the real numbers are in. It covers the gap between what a pay run calculated and what the rep actually earned, usually because data landed late or because a rate depended on a period-end total nobody knew during the period.
Software licensing borrowed the same word for an annual reconciliation of seat counts. In sales compensation it means something simpler: the payment that closes the distance between an estimate and the answer. The term appears in commission statements far more often than in plan documents, which is the first clue that most true-ups are unplanned.
There are three causes and they deserve to be told apart. The first is structural. A plan with retroactive tiers, an annual accelerator, or a quarterly kicker cannot be calculated exactly on a monthly cadence, so the monthly runs pay a conservative estimate and a scheduled true-up settles the difference. That is a healthy true-up. It was designed. The second is late data: a deal that closed inside the period but reached the system after the run had already been calculated and sent to payroll. The third is an error found in review. Only the first should be routine, and a team that sees the second and third every month has a data problem wearing an accounting word.
True-ups run in both directions. A correction that reduces what a rep was paid is still a true-up, though it is often called a true-down to make it sound less like taking money back, and it shares most of its problems with a clawback: it arrives late, it shrinks a paycheck the rep had already spent, and it needs an explanation a person can follow. Plans that only ever correct upward are not being generous. They are quietly carrying an error rate that only gets fixed when it favours the payer.
The plan pays 5% on quarterly production up to $200,000 and 8% on everything once that mark is crossed, applied retroactively to the first dollar. Monthly runs pay at 5% because nobody knows yet how the quarter will land. The true-up settles it after month three.
The correcting payment is larger than any single month's commission, and it arrives in a pay period after the one that earned it. That is a cash flow event for the rep and a withholding event for payroll, and both are easier when the statement says which quarter it belongs to.
The adjustment lands in the current pay run, the statement shows it as this month's earnings, and three months later nobody can establish whether the Q1 correction was ever made or was made twice. Every true-up line needs three things attached: the period it corrects, the run it is correcting, and a one-line reason. Without them the year-to-date figure on the rep's statement and the accrual in the ledger drift apart permanently, and the reconciliation that would have caught it has no way to match the two.
The long form lives in the guides: Plan templates.
Commish pays true-up the way your plan describes it, shows the arithmetic on every line, and traces each payment back to the deal that earned it.