DSXchange

You are not getting it.
In some low level operations, if you divide integers, the decimal part is dropped.

1/12 = 0.0000 in integer math.
anything to zero power is 1.

add the decimal explicitly and see if you get the right answer. Put 1.0 where you have 1, etc.

I have tried below in transformer and got the expected results.
pwr( (1+(-2.0/100)),((1.0/12)-1))

convert the incoming columns to floats and this should resolve the issue.