I need to sum multiple columns based on the value in one column and
the excel formula I used below always evaluates to 0 and I can't
understand why?

=SUMIF($AC$155:$AC$334,C62,$AM$155:$AR$334)

Here's some sample data assuming c62 = 1

AC AM AN AO AP AQ AR
Year ...... Cost 1 Cost 2 Cost 3 Cost 4 Cost 5 Cost 6
1 0.00 83.61 0.00 0.00 0.00 0.00
1 0.00 83.61 0.00 0.00 0.00 0.00
1 0.00 83.61 0.00 0.00 0.00 0.00
1 0.00 83.61 0.00 0.00 0.00 0.00
1 0.00 83.61 0.00 0.00 0.00 0.00
1 0.00 83.61 0.00 0.00 0.00 0.00
1 0.00 92.01 0.00 0.00 0.00 0.00
1 0.00 92.01 0.00 0.00 0.00 0.00
1 0.00 92.01 0.00 0.00 0.00 0.00
1 0.00 92.01 0.00 0.00 0.00 0.00
1 0.00 92.01 0.00 0.00 0.00 0.00
1 0.00 92.01 0.00 0.00 0.00 0.00
2 0.00 92.01 0.00 0.00 0.00 0.00
2 0.00 92.01 0.00 0.00 0.00 0.00
2 0.00 92.01 0.00 0.00 0.00 0.00
2 0.00 92.01 0.00 0.00 0.00 0.00
2 0.00 92.01 0.00 0.00 0.00 0.00

Thanks for any input.

AJ