The user's anxiety is understandable, but it's also misplaced. Their finance background has already given them the core toolkit for this interview; the challenge isn't learning new functions, but learning how to deploy the ones they know under pressure. A 30-minute Excel technical is not a test of obscure formulas or memorized shortcuts. It is a test of structured thinking and operational speed within a defined scope.
For someone comfortable with XLOOKUP, INDEX-MATCH, SUMIFS, and pivot tables, the "advanced functions" the recruiter mentioned likely refer to nesting these tools together under time constraints. The gotchas will be predictable: an unsorted table breaking a VLOOKUP, a missing absolute reference dragging down a formula, or a pivot table not refreshing after a data change. These are not traps designed to fail you. They are tests of whether you can audit your own work in real time. The best practice for the next week is to take three raw datasets, any public data on company headcount, regional sales, or budget allocations, and force yourself to produce a clean summary table in under 10 minutes each. Do it twice, then do it again with a timer.
What separates a candidate who passes from one who impresses is not raw speed. It is the ability to explain the logic behind a formula while building it. In a consulting context, your spreadsheet is not a personal calculation tool; it is a communication device for a client. The interviewer wants to see that you can structure a solution that another person can follow. So when you build a nested IF inside a SUMIFS, narrate the steps aloud. That habit will earn more credit than finishing two minutes early.
Your foundation is solid. The only thing missing is the discipline of the timer and the habit of verbalizing your process. Focus on those two things, and the test becomes a demonstration of what you already know.