Bank of Queensland's managing director, Stuart Grimshaw, has provided a more discursive view of the bank's handling of its review of asset quality earlier this year, which led to a 30 per cent rise in its level of impaired assets (to A$579 million) and to the bank's half-year loss.Asked at yesterday's investor briefing by Matthew Davidson, from Merrill Lynch, to explain management's approach, Grimshaw - who only joined BOQ in November 2011 - said the bank was seeing "realisations of property coming through which actually were outside what we would call the normal distribution of outcomes. "We were looking at valuations which were probably between one to three years old, and, with our geographical dispersion towards south-east Queensland, one year in property in the south east is a very long time. "And we found that, even since the balance state of August 2011, the market had probably gapped another 10 to 15 per cent. "It caused us to look at what really is the provision that we should use."Grimshaw said the review did find "weaknesses", while "the model wasn't as dynamic [as it should be] given the rapid shifts in property prices that we had seen."