I have a formula that gives me a total of submissions in a particular month. It is the following, where column E is the date: =SUMPRODUCT((MONTH('Sheet1'!$E$2:$E$99)=1)+0)+SUMPRODUCT((MONTH('Sheet2'!$E$2:$E$100)=1)+0) -- January's total

This formula works for all the months I already have it (starting in June of last year), but when I updated it for January (see above, by changing the MONTH formula), I am getting erroneous values, where the total is far too high. I do not know nor understand why this keeps happening. Any insight would be greatly appreciated.