The problem with recovery rates is that they different by orders of magnitude across different borrowers and credit products (for example car loans are around 70%, industrials are a bit loweer at 40%-50%, and high yield credit cards are single digits) so if you have a random sample of credit products in a portfolio it will approximate 40%. What generally happens is that the bank will sell it off to a specialist distressed investor long before the bankruptcy event so 40% is both wrong and not a horrible number to go by.