Another operational blunder at the Bank of Queensland will cost the bank A$46 million to remedy, or about one month's profit. The bank said yesterday that it had incorrectly applied interest rates and fees on some products, affecting four per cent of customers. Refunds to customers will cost $35 million and system changes will cost $11 million.Some of the problems date back to 2004, around the time BOQ made the shift to the Fiserv core banking system.Fiserv cannot have fostered the productivity benefits claimed for it by bank management at the time. BOQ yesterday blamed the problems, in part, on "overly complex products which required too many manual processes."Affected products included "packages" that allowed staff to modify terms.BOQ said the issues emerged following a "detailed review of our products, processes and systems."It said that, as part of the product review, "We have assessed a broad range of areas from branch security through to disaster recovery plans and lending processes."One impetus for the review was another operational glitch, relating to "mortgage offset account issues", late in 2012. This episode cost the bank around $12 million.In March 2012, BOQ was obliged to lift lending provisions by $262 million, after many problem loans emerged.Losses from these legacy issues added  $320 million, or 12 per cent of the bank's net assets, at the time of the hand-over from David Liddy to Stuart Grimshaw, as new chief executive, in August 2011.To temper investor ire over the latest loss, BOQ said that its pre-tax profit for the year to August 2013 would be "at the top end of analysts' consensus range of $339 million to $368 million."The bank also said it "remains on track to achieve six of its seven previously stated [2012/13 financial year] management targets around asset growth, margins, expenses, bad and doubtful debts, and returns."It said, "The exception is retail asset growth of one times system, which, on present experience, will be broadly in line with the 0.8 times system outcome reported in [the first half of the 2012/13 financial year]."BOQ said it expected the final 2013 dividend payment "to be at least equal" to the interim dividend of 28 cents per share.