Although I appreciate that "Catch-22" technically relates to the circumstances in which aircrew could or could not be considered "sane", the underlying problem of shifting groundrules for what constituted a tour of duty came up a couple of months ago and attracted a good number of responses. While you're waiting for fresh replies, you might like to review that earlier thread, led by always excellent u/the_howling_cow and u/Bigglesworth_

In Catch-22, whenever the pilots of Yossarian's group approach the number of bombing missions required to be sent home, the number required is adjusted upwards. Did Joseph Heller base this scenario off of actual practices during the second World War?