A
Thanks, Charlie. Naming the headers and the format in the prompt is exactly the kind of detail that saves the most time, and the dates-stored-as-text trap is one I see constantly in training sessions. Testing the formula on three rows you can add up by hand, including one edge case, is a habit I’ll recommend more explicitly. Asking Copilot to list the row numbers and the rule it used for the outliers is also a good way to check the logic instead of trusting the highlight. Have you found other prompts where this kind of check catches errors?