Lowered my Mortgage Rate

I read in the Australian Financial Review that having an offset facility usually means that the mortgage interest rate that you are paying is higher and that this gap is biggest at the Commonwealth Bank, where we have our mortgage and offset account. The article said that the gap could be as big as 1.91%! I don't remember this being explained to me when we got our mortgage and offset account though I did discuss with the salesperson whether we should get an offset account. 

I have wondered why our mortgage rate was so high and tried to move our mortgage to HSBC to get a lower rate. They just continually ran me around and nothing ever happened. So, I gave up on that.

So, I phoned the bank and he told me that I should phone regularly to "review my discounts", which I have never done. Basically, there is a seniority discount - the longer you are with the bank the more the discount. So the standard rate for the offset account is actually 6.3%. I was paying 5.4%. He increased the discount from 0.9% to 2.29%, lowering my mortgage rate to 4.01%. If I switched to the no frills product cited in the AFR he could only give me a 0.2% discount off the 5.53% standard rate. 

I estimate the gain in net worth at the end of the mortgage, assuming we don't pay off the mortgage any faster, is AUD 271k at 6% inflation and AUD 188k at 3% future inflation. The saved interest is in the ballpark of AUD 90k. It feels weird to earn that much for about an hour's work.