I have an excel formula that is working in one spreadsheet but not in another. In the 082018 tab the formula is working but not in the 052018 tab. The formula's are in Columns E-O.
Since in the latest sheet in column AK you have dates entered as text. You may check with formula like =AK1088+1 which returns error.
To convert text to dates select the column and on ribbon Data->Text to Columns, on third stage of the wizard select Date and MDY.
Perhaps some other columns as well are texts instead of dates/numbers, I didn't check all of them.