Variable compensation is the portion of pay that depends on performance: commission, bonuses, accelerators, incentives and overrides, meaning everything outside guaranteed salary. It is earned rather than accrued, it moves with results each period, and in a sales organisation it is usually the largest payroll line that nobody can forecast exactly.
Payroll divides cleanly into money that arrives and money that has to be produced. Base salary, benefits and allowances are known in January for the whole year. Variable compensation covers everything on the other side of that line: commission on revenue, quota bonuses, accelerated rates above target, short-window incentives, management overrides, and anything else whose amount is settled by what happened rather than by what was agreed in advance. Finance books it as a forecast and reconciles it every period, which is why the variable side generates most of the questions, most of the disputes and nearly all of the month-end work, while the fixed side generates a single journal entry.
The forecast misses for a reason that surprises people the first time they watch it happen: total variable cost does not track team attainment. Accelerators mean an overperforming rep costs more per point of attainment than an underperforming rep saves, so a team landing at 97% of its collective number can still run through its variable budget. The shortfall sits with reps earning below target at the plan rate, the excess sits with reps earning above target in accelerated bands, and the two do not net out. Distribution drives the bill far more than the average does, which makes a plan modelled only at 100% attainment a plan modelled at the one level almost nobody lands on. Model the tails instead, at both ends: what this costs if three people have the year of their careers, and what it pays the person having a bad one.
Ten reps, each with $50,000 of variable pay at target, so $500,000 of planned variable spend. Commission pays straight through to target and accelerates at 1.5 times for attainment above 100%.
Each overperformer earned $72,500 against a $50,000 plan while each underperformer saved only $20,000. The team finished three points short and the compensation line finished $7,500 long. Widen the accelerator or the spread of results and that gap grows quickly.
The long form lives in the guides: Commission structures.
Commish pays variable compensation the way your plan describes it, shows the arithmetic on every line, and traces each payment back to the deal that earned it.