When you have to resort to this many nested IF functions it is generally a case of inefficient design in the workbook. I suggest you post a sample workbook that meets the following criteria . . .
1. EXACTLY duplicates the structure of your real workbook, and
2. Contains representative but non-sensitive dummy data, and
3. Manually shows a couple of expected results per your conditions

You should probably consider using a look up table and / or helper columns.