How to calculate 2 fields divided by a condition

Actually yes it did.
I had a Mismatch aggregation issue and I tried the formula provided on the answer, but it failed again until I went back to a previous formula to calculate de CLR% and PRS% with the syntax correction.

I realize is the same solution that is on Mismatched aggregation issue

So I change the formula order, instead of start with ifelse I started with sum (ifelse…) to:

sum(ifelse ({Concession Type Code} = “reversal”, {# correct reversal}, null))/count({total reversal})

that’s it, thanks to all.