This is the correct formula: =LOOKUP(C12,BB17:BB21,BD17:BD21)*MAX(1,1.0154*((D29+D30+D31+D32)/D37)^2+1.1759*((D29+D30+D31+D32)/D37)+0.3633)*G20*IF(C15=TRUE,0.5,1)*(1-N15)*IF(C4=Y14,0,1)
There was a small error in the hypnotic series of parenthesizes~