Bank of Queensland has identified errors in its compliance systems that have resulted in customers being overcharged on fees and underpaid interest.The Australian Securities and Investments Commission issued a statement yesterday, saying BOQ had confirmed that it would refund A$34.5 million as a result of these errors.This payout is on top of a $12 million error that BOQ reported to ASIC last year. In that case, some mortgage offset accounts were not linked to home loan accounts for several years. As a result, borrowers paid more interest on their mortgages than they should have.After the initial error was uncovered, the bank appointed an independent expert to review its compliance systems. BOQ has agreed to a request from ASIC to expand the scope of the review.Altogether, these problems have affected 46,000 customers. On top of the payouts, BOQ will spend $11.5 million on remediation.