I don't see the relevance of "NX-74205" (24th Century) for the NCC numbering scheme of the 23rd Century. I'd say that within a period of 100 years certain methods or nomenclatures will undergo some form of change and this might just be it.
There is nothing on screen to indicate any rhyme or reason to the registry numbers on starships. I was just pointing out how Jefferies' 17th ship design, 1st build template could be used despite there being an NCC-1700, which doesn't seem to fit. It makes just as much sense to have NCC-1700 be the first ship of the series, or have the first ship of the series/class be NCC-1681 for that matter. Nothing on screen says that Star Ship/Constitution/Enterprise have to have registries that start with NCC-17xx.
While I'd say the 17th design should start with a "17", I agree that the last two digits might merely be a random assignment and/or the actual (Naval Contact) Code, I refer to my post # 123 in the other thread
There, we also discussed several proposals how to make sense of a registry like NCC-1697 (starship status display in "Court-Martial"). 97 starships of the 16th design? 16th cycle for all Starfleet vessels (Class ship is cycle leader) but limited to 100 vessels? "...97" indicating 17th starship built by the 5th fleet yard? et cetera
is NCC-602, USS Enterprise
is (coincidentally?) NCC-1701, USS Excelsior
is NX-2000 (had it been "2001" I'm certain most people would have agreed it should have been USS Discovery...)
and the TNG Stargazer
-type USS Constellation
supposedly carries (or from a TOS point maybe could be) NCC-1974.
Theoretically, the NCC-1831 on the starship status display could have referred to the USS Miranda
(class leader of the 18th design).