I'm having trouble creating a commission calculation.
The commission schedule is paid on a tiered rate (below), and occasionally there will be recoveries due to client non-payment, which comes out of commission. There is also a budget variance every month. I'd like to have the Monthly Budget in cell A1, the Revenue in cell A2, Recoveries in cell A3 and the Commission (formula) in cell A4. I only need the formula for cell A4, everything else will be entered manually.

Revenue Schedule
$0-$14,000 = 0%
$14,001 - $18,000 = 7.5%
$18,001 - $BUDGET = 10%
$102% BUDGET - Forever = 15%


Thanks for the help!