We get it. That moment when a spreadsheet formula returns 0.9999 instead of 1.0, even though every person worked full-time all year, is the kind of frustration that makes you wonder if the tool is working for you or against you. The user who posted this question found a clean fix: move the rounding out of the intermediate column and apply it only at the final average. Simple, elegant, and it solved the problem. But the real lesson here isn't about where to put a ROUND function. It's about how easily small choices in spreadsheet design can erode trust in your data.
The original approach made sense on paper. Round each weighted period to four decimals, then sum those rounded values. The trouble is that rounding introduces tiny errors at every row. When you add up a year's worth of those errors, a person who truly worked 1.0 full-time equivalent shows up as 0.9999. That's not a bug. That's arithmetic. The fix, rounding only the final result, preserves precision through every intermediate calculation. It's the difference between measuring with a ruler that snaps back to zero after each inch versus one that lets you read the full length at the end.
What this means for you is straightforward: your workforce data deserves the same care you'd give a financial model. One misplaced ROUND can misrepresent headcount, skew budget allocations, or create discrepancies that someone has to manually explain in a meeting. The user's edit, "moving rounding to column E instead of D did the trick", is the kind of practical insight that separates a reliable report from a spreadsheet that produces artifacts. It's not about knowing every function. It's about understanding what each one does to your numbers.
If you're managing staff data, take this as a reminder to audit where you're rounding. The goal isn't perfection down to the fourth decimal. It's accuracy at the level that matters for your decisions. Let the intermediate calculations breathe. Round once, at the end, and your averages will reflect reality, not the quirks of your formula. That's the kind of precision that turns a spreadsheet from a source of doubt into a tool you can actually rely on.