After spending ages trying to check the brackets, I see this is a formula that, I assume, is working in a different model. That will teach me for not reading the question properly!
FYI, This is what I got when changing all the If statements to If(Condition,True,False)
I think the general properties tab has the field type set to character. Please try and put the entire expression inside quotes :
Please could you check that the ServiceDate is a genuine Date/Time field and the mcrsd2016 (etc) and Qty are numeric.