Another solution:

Make a helper table of multipliers in Sheet2:

A B C D E F G H
1 Mon Tue Wed Thu Fri Sat Sun
2
3 Normal Hours 1,0 1,0 1,0 1,0 1,0 1,5 2,0
4 Hours x 1.5 1,5 1,5 1,5 1,5 1,5 1,5 2,0
5 Hours x 2 2,0 2,0 2,0 2,0 2,0 1,5 2,0

You need only a single formula:

=$A$1*B3*INDIRECT("Sheet2!"&ADDRESS(ROW()-3,COLUMN(),4,1,))+$A$1*B4*INDIRECT("Sheet2!"&ADDRE SS(ROW()-2,COLUMN(),4,1,))+$A$1*B5*INDIRECT("Sheet2!"&ADDRE SS(ROW()-1,COLUMN(),4,1,))

Regards,
Stefi