I have a Google Sheet in which users key in records for a specific month. A report on another tab looks up the month and consolidates it. I'm trying to enforce using the first day of the month to match the header in the report sheet. (I know I could replace the lookup with a sumif range, but I'm trying to keep the formulas as short as possible and the amount of calculation to a minimum, since this ends up being a large document)
I've set a Data Validation rule to enforce this rule, but I just looked and found numerous instances of violations, which make the report inaccurate. The rule is: =eomonth([cell],-1)+1
Mousing over the cell shows me the validation text, but the rule is set to reject the value completely! What is going on wrong here?