Making A Case Function

i am trying to get the following function to work

i want it to look at 2 cells, depending on the number in the second cell i want it to multiply the first sell by a specific number.

for exaple (Below) function in a3 looks at a2 sees it is a 2 and multiplies a1 by 1.09 shown in the code below

A1=load
A2=factor

A1 A2 A3
100 2 Function

Function Pmax(Load, Factor) As Double
Select Case (Factor)
Case "1"
Pmax = Load
Case "2"
Pmax = Load * 1.09
Case "3"
Pmax = Load * 1.12
Case "4"