More detailed expense verification and tightening of other responsible lending guidelines are not the only process changes slowing down loan approvals. The new Banking Code of Practice is also playing a part.NAB chief executive Phil Chronican yesterday said the code, which took effect in July, included process changes, particularly around guarantees, that made the loan approval process more complicated.And it is not only home loan applications that are being affected; it is small business loans as well. Chronican said the bank had a slower flow of business loan applications during the year and some of that was due to the complexities of the process. NAB is dependent on business banking relationships for a hefty chunk of its mortgage flow too.He said the banking industry's view was that the entanglement of business lending in all the new guidelines and protections was an unintended consequence of the reform process and the banks were discussing the issue with the regulators.Like the other big banks, NAB has weak loan growth during the year to September 2019.In the consumer division, home loan balances grew from A$212.1 billion in September last year to $216.6 billion in March but then fell 0.5 percent to $215.6 billion in the September half.The bank said the majority of borrowers were leaving their home loan repayments unchanged as rates came down and were paying off their loans more quickly. There was also increased refinancing.It said there was aggressive competition and conceded that it was late to market with the special home loan offers that have been a feature of the market this year.In the business and private banking division, business loan balances rose 3.5 per cent to $109 billion but housing loans fell 2.8 per cent to $88.3 billion.Mortgage arrears were up, partly because of the shift from interest-only to principal and interest. And customers are in arrears longer.The good news for NAB is on the liability side of things. Average growth in deposits over FY19 was 2.4 per cent, the EY overview of the profit season shows. NAB's deposit growth was 3.8 per cent, reflecting its business banking bias. At Westpac deposit growth was only 0.7 per cent, handy for margins but trouble in the long run.