Formulas work separately but not combined

I have multiple IF formulas nested and am running into a problem. Each IF formula works independently, but when I nest them together I run into a problem getting the correct answer. The cells with the formula that I'm struggling with are located in the attached file in column S of the REF sheet. The function of this column is to check to see if there is an existing program so we know whether we need to create a new program. After reviewing the attached TEST file and the nested formula please consider the following;
each formula works independently
the 1st through 4th formulas work together
the 5th-14th IF formulas work together
when nesting the first 4 formulas with the 5rd-14th formulas it doesn't work

I've tried putting the first 4 formulas in different locations within the 5th-14th formulas but still can't get it to work.
Does anyone have any suggestions?
Thank you for your time.