The user's frustration is entirely justified, and the solution they fear, embedding ROUND functions into every formula, is indeed the only reliable path forward. That's not a limitation of the software; it's a reflection of how spreadsheets actually store and calculate numbers. The display rounding offered by the "increase decimal" button is cosmetic. It changes what you see, not what the cell holds. When SUM adds those values, it uses the full, unrounded numbers hiding beneath the surface. The mismatch isn't a bug, it's a feature of precision that becomes a liability when your goal is exact alignment with imported data.
We understand the desire to keep things simple for colleagues who will inherit this file. Every additional function feels like a fragile piece added to an already delicate machine. But the ROUND function, used correctly, doesn't have to complicate the workbook. Wrapping your IF or IFS formula like this, =ROUND(your_formula, 2), adds only a few characters. It does not create a new column. It does not alter the logic your staff needs to adjust. It simply tells the spreadsheet to store the rounded value, so SUM sees exactly what you want it to see. The alternative, leaving the raw precision intact, guarantees the discrepancy will reappear every time someone changes a parameter.
The real insight here is that simplicity and accuracy are not opposing goals. A formula that produces wrong totals because it refuses to round is not simpler, it's broken. The staff member who changes a variable and gets a column that doesn't foot with the invoice will not thank you for avoiding extra parentheses. They will call you, or worse, they will manually adjust numbers and introduce errors that are far harder to trace. The ROUND function is not a complication; it is the guardrail that keeps the workbook reliable when others interact with it.
Our recommendation is direct: embed ROUND into your existing formulas now, test it against the imported totals, and then hand the file over with confidence. Document the change with a short comment in the cell or a note in a separate sheet, something like "All percentage calculations rounded to two decimals to match invoice totals." That single line will save your staff from confusion and save you from repeated fixes. The spreadsheet you build should empower exploration, not punish it with hidden math. Rounding is the tool that makes that possible.