This question already has an answer here:
To avoid misunderstanding, I am not really opposed to making life harder for banned users in general. Here I am only trying to figure reasons of making so in one particular case and in certain particular way (frankly, if there are such reasons this would probably make me feel better).
Banned users are allowed to post once in 6 months:
If you're unable to improve your existing questions, you'll get the chance to ask one new one 6 months after your last question.
This can become complicated if they have deleted posts affecting the ban.
If these deleted posts are older than 60 days it becomes quite difficult for user to find and check these and decide whether to wait for next attempt or maybe try to improve these deleted posts or maybe ask for help at meta (especially if they could see that time remaining for next attempt is long enough to justify investing effort in improving prior posts).
I think above can be made easier for them if the system changes the limit of showing deleted posts from 60 days to 6 months.
My understanding is, above change would be very low effort technically, kind of changing particular config parameter and editing few docs referring it in a non-parameterized way. Also it seems to be low risk because it's easy to revert if it turns out that it causes too much trouble.
So, the only reason I could imagine for keeping the current way is that it should be somehow important to make it hard for banned users to check their deleted posts for 6 months instead of current 60 days. I would like to understand the reasons why this is (is it?) important.
(Or maybe changing the parameter of showing deleted posts is indeed technically harder than I assume? To address particular question in comments, change is supposed to be done in a most technically straightforward way, that is for all users, and not only for banned ones.)