Industry analyses put the error rate in business spreadsheets somewhere between 88 and 94 percent. Most of those errors are harmless. In a fundraise, they are not.
A venture investor backs roughly one company for every 250 they evaluate, and the financial model is one of the first things they stress-test. A broken formula, or treating 5 percent monthly churn as 60 percent annual when it actually compounds to about 46 percent, reads as something larger: a team that does not yet have full command of its own numbers.
None of these are hard to fix. They are just hard to catch in your own file.