Westpac has left plenty of savings on the table for themselves (and potentially another bidder) on the basis of the broad brush financial details on the proposed takeover of St George Bank published yesterday.For its part, the board of St George Bank left the door ajar to an alternative offer.The two banks yesterday signed off on the merger implementation agreement and spelled out the likely timeline for Westpac's takeover of St George. Westpac has offered 1.31 of its shares for each share in St George.The need to secure regulatory approvals (mainly from the ACCC but also APRA and the Treasurer) and the fact that the takeover of the fifth-largest bank by the third-largest raises plenty of competition issues means than that the timetable is quite drawn out.St George does not expect to send out documents to shareholders for the meeting to vote on the proposed scheme of arrangement until well into October and the two banks do not expect to close the merger until the second week of November, based on the timetable published yesterday.At in excess of five months the merger timetable is similar to that for Suncorp's takeover of Promina two years ago but a lot longer than ANZ's takeover of National Bank of New Zealand.Westpac said in a presentation lodged with the ASX that it expected pre-tax savings "equivalent to" 20 to 25 per cent of St George's cost base by 2011 (but with cost savings achieved across the combined group).The rule of thumb in bank takeovers used to be that savings of between 30 and 30 per cent were achievable.In the case of the Westpac bid for St George the former plans to retain the branch network of the latter.Westpac did not spell out any forecast of incremental revenue from new sales opportunities and said it allowed for revenue attrition of five per cent.The bank drew parallels with the Royal Bank of Scotland takeover of BankWest in Britain in 200 where attrition was less than five per cent, and also with the ANZ takeover of National Bank of New Zealand in 2004 where the combined group maintained market share over time.Westpac said it expected to incur integration and transition costs of $700 million over two years, but did not break this down or care to spell out a more detailed timetable. The bank did clarify that technology costs would represent less than half this estimate.The bank reiterated that it expected the takeover of St George to be accretive for earnings per share in the third year. Phil Coffey, Westpac's chief financial officer, in answer to an analyst's question, said: "I think when looking at return on capital, I think for a bank the real measure you need to look at is return on equity, and as you'd expect the accounting on return to equity on this transaction will take a near term hit as a consequence of the goodwill that we take on board, but we would expect that to recover over time."Meanwhile, in what may