Prove Compass matches your bank. For each account, Compass adds its starting balance to every transaction since, and you enter what the bank actually shows. If they match, your data is complete.
How the math works (no AI, no guessing): Computed balance = your starting balance + the plain sum of every transaction since that date. That's it — addition. You compare it to your real bank balance. A gap means a transaction is missing or duplicated, not that a number was "calculated wrong."