It could reasonably be argued that this is a problem that only the Tour cares about, and then compounds within our own nomenclature.
The table was set all the way back in The Deadly Assassin which set a 12 regeneration limit for Timelords. While that might seem a bit archaic in 2022, back in 1976 this was a significant, and in some corners of fandom at the time, controversial limitation put on the program. It was also remembered as a plot point for The Ultimate Foe and, ultimately, by Steven Moffat in 2013 when he had an Eccleston-sized hole he had to fill for The Day of the Doctor. The revelation of John Hurt’s ‘War Doctor’ paired with David Tennant’s ‘hand’ from The Christmas Invasion and The Stolen Earth got Doctor Who, as Matt Smith’s Doctor stated himself in The Time of the Doctor, to the canonical limit of 13.
It also created the schism which has, essentially, forked Doctor numerology ever since. No one really thinks of John Hurt as the ninth Doctor so the Tour finds ourselves increasingly out-of-step with the rest of Doctor Who fandom, particularly when, at the end of The Power of the Doctor, Jodie Whittaker gives way to David Tennant–again. And given that all of the publicity keeps referring to Tennant as the 14th Doctor and Ncuti Gatwa as the 15th, we have what Tennant himself referred to in The Christmas Invasion as a ‘great big stinking problem.’
For public purposes does this mean that Tennant is not only the 10th Doctor but also the 14th? In the realm of the Tour Tennant is not only the 11th, but the 12th–as the hand (savvy visitors have noted that the Tour has no real 12th Doctor choosing instead to push out his remaining stories as a continuation of the 11th) and soon to be the 16th?
Knotty, knotty.
And this doesn’t even consider the notion that whatever adventures Tennant and Catherine Tate have in November 2023 are not some new Doctor altogether but some hitherto weird Doctor variant/cul-de-sac which RTD will explain away before Gatwa fully comes aboard.
But will that be as the 14th Doctor following Whittaker, the 15th as publicity flatly states, or the 17th Doctor since the Tour sees Whittaker as the 15th?
Of course, you could hang the sense of all of this and just let things play out. But where would the fun be in all that?