Mitchell's date of birth was "1087.7" (age 23)
Dehner's date of birth was "1089.5" (age 21)
Well, both bits plausibly equate the last two digits with years, but these don't agree with each other when it comes to the first two digits. That is, the latter clearly has them as being the same as the last two, that is, rolling over like centuries and millennia, yet Kirk and Mitchell obviously must be from the same century.
What are the odds of that being deliberate and done by one and the same person? Or it being deliberate and done by two people who had the exact same idea at the same time but never cross-checked? Lower than it being a complete coincidence, I'd wager. (This wholly apart from the behavior of the stardates punctuating the episode itself, establishing a rapid progression of the digits flanking the decimal point, within the at most days that the episode takes. A third guy doing unrelated creative work?)
Not that this should make the explanations offered any less plausible as in-universe rationalizations. It just looks as if this doesn't wash as a story of how the numbers were chosen in the real world.