In addition to the reply posted by @hanlonhart, I’d mention that the reason why revoking a cert doesn’t restore your limit is because the current limits are not there to restrict the number of active certificates, rather the number of issued certificate to make sure that the resources available are properly distributed among all the users.
You use LE issuance resources when you request a certificate, not depending on the state of the certificate itself. They are rate-limiting issuance.
And then someone will come, and say that for him the best limit is 25 because he needs 21. It’s a never ending story: whenever there is a limit, there will always be someone who think he deserves a larger limit.