I suspect the reason Bush won’t let his Service Records to be released is they will show he accepted pay for dates he did not show up.
I mean, we already know he never completed training to become a fighter pilot because he stopped flying rather than take a physical after they announced a new policy of drug testing. He already admits there was quite a bit of time he wasn’t there. (He claims he made it up.) His “honorable discharge” papers show that he left a year early. So what does he still have to hide? Why won’t he allow the records to be released?