But it can like when FSD Beta 10.3.1 (2021.36.5.3) went to about 2% already on 2021.36.5.5 and maybe even 1 vehicle on 2021.36.8:
The release notes and other metrics for the Tesla software update, 2021.36.5.3.
teslascope.com
And "downgrading" from say 2022.4.5.16 to 2022.4.5.15 could still include everything in the "larger" version as Tesla can allocate version numbers (especially the 4th number) however they want without strict dependencies on previous versions. Tesla knows they need a different version for merging in FSD Beta behavior, so .15 and .16 could have been created at the same time knowing both would have the same bug fixes.
If Tesla used 5 numbers for versions, FSD Beta 10.11 could have been 2022.4.5.16.1 instead to perhaps more clearly identify that the FSD Beta version should include everything from the "parent" version. I suppose why didn't Tesla version 2022.4.5.16 as 2022.4.6 instead so that FSD Beta could be 2022.4.6.1?
Maybe internally they have some special meaning for the 3rd number, but seeing how they picked 2021.44.25.* for the Holiday/Christmas update, it seems like it can be pretty arbitrary as well (whereas the first 2 numbers are date based).