Cameron Clyne, chief executive of National Australia Bank, opened the door to the bank taking a more independent line on the timing, and also the level, of interest rate rises (or cuts) in the future."The main driver of bank interest rates is not the Reserve Bank cash rate," he said."The banks have made a problem for themselves here by continually moving in line with the Reserve Bank."Clyne said that "the reality is that it is not the driver of our funding, but we have for many, many years created that perception to the public."We've got to face the fact we have created this through our own poor communication of the issue."If the banks continue to move with the RBA up or down then we are compounding the view that our funding is tied to the cash rate."So I think there is some merit in banks making their own decisions independent of the RBA."Clyne, along with the bank's executive director, finance, Mark Joiner, told the committee, they questioned the analysis by the Reserve Bank of Australia and Treasury. Both had understated the rise in the cost of funds being experienced by banks in Australia, he said.Joiner said Treasury and the RBA put the rise in the cost of funds at between 90 basis points and 100 basis points over the crisis. However, Joiner said, NAB put the rise at between 110 and 120 basis points. The reason, he said, was that the RBA and Treasury "lacked data. They don't see what we see," he said.On the other hand, Clyne emphasised a number of times that the bank now put an overview of its cost of funds up on its website and updated this regularly, so, as one committee member pointed out, regulators ought to have access to enough data.