XLOOKUP is a powerful function, but it has a blind spot: it returns only the first match. The user who posted this question has run into a common limitation, when a person makes multiple payments in a month, XLOOKUP finds only one of them. That is not a failure of the user's formula. It is a structural constraint of traditional lookup functions. And it points to a deeper truth: the tools we rely on were built for a world where data behaved neatly, and in practice, data rarely does.
The solution here is not to keep stacking XLOOKUPs or nesting IF statements into a fragile tower of logic. The approach that works is to shift from a lookup mindset to a summation mindset. Instead of asking the spreadsheet to find one value, ask it to find all values for that person and add them together. That is exactly what SUMIF or SUMIFS does, and in this case, SUMIFS is the more flexible choice because it can handle multiple conditions. For John Doe, the formula would look like this: =SUMIFS(January Commission Listing!$C$1:$C$342, January Commission Listing!$B$1:$B$342, B3). It checks every row in column B for the name in B3 and sums every corresponding value in column C. No hidden duplicates. No missed payments. The result is a single, correct total.
What this reveals is that the user's real need is not a better lookup. It is a more complete understanding of their data's behavior. Many people turn to XLOOKUP because it feels modern and direct, but when the data contains duplicates, it becomes a bottleneck. The better tool is not a fancier version of the same logic, it is a fundamentally different function designed for aggregation. That is the kind of shift that AI-native tools can make automatic: identifying when a user is hitting a structural wall and suggesting the right alternative without requiring the user to know the difference between lookup and sum functions.
So the practical takeaway is direct: if you are using XLOOKUP and finding that it only grabs the first payment, stop trying to force it to do what it cannot. Use SUMIFS instead. It is not a workaround. It is the right tool for the job. And if your spreadsheet tool cannot surface that recommendation on its own, then it is still treating you like a programmer when you are really just trying to get a clear answer about your business. That is the gap that needs closing.