IF function HELP

I'm looking to selectly check my data using the if function

I want to check all of column N to match "FRM" then only the once that matches "FRM check column G if it is less than 5 years (60 mths) and greater than3 years (36 mth) then only those cells that boatches both arguments check if column C is great that X if yes then output "Yes" if no then output "no"

But I don't think this is working... anyone know why? should I use an array formula?
=IF(Conventional!N5:N509="FRM",IF(Conventional!G5:G509<=36, IF(Conventional!G5:G509<=60, IF(Conventional!C5:C509>=(O30+1.15),"Yes","No"),"No"),"No")


Thanks,