The third bank to join the Standing Committee on Economics review of Australia's four major banks - for its third hearing - was National Australia Bank. Its executives were more forthcoming in front of the of pollies last Friday than in the previous two hearings.NAB CEO Andrew Thorburn opened his presentation by explaining that small business contracts have been reduced in length by approximately a third after they were rewritten in plain English and many clauses seen as irritations were cut. He was also keen to point out that NAB's ATM network has limits in place preventing any deposits greater than A$5000, and said Austrac had advised it had no problems with this.Committee chair David Coleman asked Thorburn why NAB chose a limit of $5000 for deposits into its Intelligent Deposit machines. "In the process of choosing that limit, were higher limits considered?" he asked.Thorburn said NAB's view was that, after initially considering $10,000 as the limit they should work back from that to a buffer. "We felt $5000 was a far more appropriate limit, and for customers, mostly, that was fine."As with other Big Four execs, NAB execs were tested on PayWave (also known as tap and go) which involves the cost of debit card transactions being routed through the card networks, rather than via eftpos - a move said to be costing small retailers $200 million annually.They were asked if NAB would match ANZ's commitment to allow merchants to change machines to have eftpos as default. Thorburn demurred at first, commenting that many customers preferred to use credit or debit cards because they get rewards.Coleman disagreed with this, saying most customers were not aware of the situation and added that, in the vast majority of cases, rewards do not pertain to debit cards (only to credit cards).NAB chief operating officer Antony Cahill responded that: "the average transaction by contactless is $35 and new information is expected to show that the cost to the merchants for Visa or eftpos will be very close."Thorburn added that the bank's view was "if customers want an eftpos product they can have an eftpos product - we have one million of these on issue."He was also proactive on sharing data, explaining that under a comprehensive credit reporting scenario, where there's a loan of up to $3 million and the borrower has been meeting loan payments, but the loan to value ratio changes due to a revaluation of the asset (for example a farm), that will not trigger a default, as had happened in the past.In another notable development, NAB admitted to wholehearted preparation for open data, despite an apparent long term public rejection."Our view is there is more competition coming into the industry and the more information we receive about our customers, the better-informed credit decisions in terms of differential pricing we can make," said Cahill."We looked at this [open data regime] and felt it was right thing to do so we thought we would go and start building our understanding and capability.