That all being said, we as fans must reconcile things like this, because we sure as hell aren't going to write off TMP as 'never having happened'!
I don't remember whether, and to what extent if so, fans like me even tried to reconcile "things like this" before 1993-94, when the Okudas' Chronology and their Star Trek Encyclopedia (which had a lot of content overlap with the Chronology) were first published. The publishers, Pocket Books, weren't fools and correctly predicted that fans would be attracted to these entertaining works. But no, we don't have to feel compelled to reconcile dates. Even back in 1966 there were inconsistencies with regard to elapsed time (see In The 23rd Century . . . discussion concerning "The Squire of Gothos," for example).