the formula shoud be like this
if the [CellXX] is "XX" then calculate the incentive through this IF
formaula or
if the [CellXX] is "YY" then calculate the incentive through this IF
formula or
if the [cellXX] is "ZZ" then calculate the incentive through this IF
formula of
if the [CellXX] is "AA" then calculate the incentive through this IF
formula


For one possible approach, start with
=LOOKUP([cellXX],{"XX",1;"YY",2;"ZZ",3;"ZZ",4})
and replace 1, 2, 3, and 4 with the four IF formulas.