With interest rates remaining flat and at rockbottom, the easy - and profitable - spread of loans to deposits has not been open to Australia's banks.Part of Westpac's answer has been to boost profits by cutting costs through technology - and to be accountable for progress.In Westpac's review of group operations for the half-year to March 2015, one measure of the effectiveness of its digital transformation strategy will be whether the cost to income ratio can dip under 40 per cent."For the first half of 2017, the Group's expense to income ratio declined 59 basis points to 41.7 per cent, although this was a little higher than the ratio recorded by Westpac in the first half of 2016," the report noted.The practical effects of further "digital adoption" was that the group ran its network across Australia and New Zealand with a net reduction of 45 branches over the half. Group-wide, Westpac's ATM numbers also dropped over the last six months (down 15), but the number of smart ATMs (that is, more fully featured) increased three per cent and now represent almost 40 per cent of the Westpac Group's ATM network.In a media conference to discuss the half year results, CEO Brian Hartzer and CFO Peter King were coy on what their optimum branch and ATM network would look like.  "We don't have a branch number in mind," said Hartzer."Over the counter transactions are falling pretty significantly as people move online. But branches are really important for customers to go and have a conversation with one of our staff."We also recognise retail patterns are changing and like any retailer we want to ensure that our branches are located in the spots where it's convenient for customers to go. We see this as an evolution over time."He conceded this will probably mean fewer locations, different types of branches and a lower cost per branch, "so there will be savings from that [strategy] as well."The big savings, though, are not in cutting branches. Those savings will be found in the paper processes and rework of those manual processes. The major opportunity in that area, one where the group should be able to reap plenty of cost savings, is from eliminating the final duplications among the back-end systems currently being run for the Westpac group and for the St George group."We are trying to use technology to go straight from the customer all the way through the system in a way that makes it cheaper to originate a loan or new account," Hartzer said.Developments in this area have included digitisation of manual processes for mobile personal loan applications, "materially speeding up the time between application and receiving funds," according to Westpac's half year review.