A gap between the bank statement and your own records is normal: a collection is entered today but the money lands tomorrow; a charge shows at the bank before you know about it. The problem is not that a difference exists, but that it cannot be explained.
The bad fix is to post every statement line straight into your books. Then the same collection is recorded twice and your customer's balance is wrong.
The right order is: bring the statement into a separate area, match each line to your own record, and review what is left. When you upload a statement, Kumpara writes nothing to your books; it suggests matches by amount and date, and you decide. Where a line has no counterpart, you can create the collection or payment from there.
Uploading the same file twice never duplicates movements — which matters if you like to check again mid-month.