IN the attached spreadsheet, in column F there is a calculation for the minimum payment due in the following month.

What I've having difficulty with is calculating the amount paid up to and including the 20th day of that month, and then comparing that to the amount that was supposed to be paid, showing what, if any, overage or shortage in payment occurred.

I'd like this in column G.

Since the dates and amounts seemed relevant to solving this, I didn't anonymize that data.

My preference is a solution for OpenOffice, though I do have both Open and LibreOffice installed.