This is an answer to Frank's question about using the date picker for computations. I made it a seperate post as I attached the MZP file.
My proposal for that problem:
1. Filter the values of your excel by using the "Filter operator". Use as condition a user input that provides the required date (month).
2. Compute the quotient ev/ac using the "Arithmetic" operator
3. Compute the sum of the quotient by using the "Aggregation" operator
You can now you the input of this feed to parametrize the month you want to aggregate:
This should solve your problem. Please try the attached MZP.
Regards, Tobias