Canned reports created with a report writer within AC may or may not have the correct calculations but those are much different than the raw data. I believe you can still rely on the raw data for whatever purpose you need, including giving it to the accountant.
An export from the database is just that: the raw data that your office has entered. There are no reports or calculations involved. All calculations are done outside AC within MSExcel. If you screw up the tally of a column, there is no one to blame but yourself.
