No its not misleading. The character at the top of the list gets the most XP. What you write is a more detailed explanation but doesnt contradict what I said, instead confirms it. Also I was aware of these details already. Sorry if my explanation was apparently not detailed enough.
It gets even more complicated with multiclasses, because a double multiclass can only accept even XP rewards, and tripple multiclasses only XP rewards divisible by 3.
If you want details, yes technically Charisma 16 (as well as 17) is kind of supposed to be good on paper, but the game treats you a lot like you have average charisma if you dont have the absolute maximum possible, 18.
Pretty much like the game (or rather AD&D) treats you like you're basically average clumsy unless you have at least Dex 15, otherwise you get no bonus. And as if you have no strength unless you have at least Str 16, and even then the bonus is minimal compared to 18/xx.
In AD&D you usually want 18 or bust. For example a fighter with Str 17, Dex 17, Con 17 is far worse than a fighter with Str 18/xx, Dex 15, Con 18, even if by pointbuy thats the exact same number of points. Though that also depends a lot upon the xx in 18/xx, too. You want 18/91+ or ideally 18/00, really, but at very least 18/76+.
Well, except in some cases its different - non-warriors dont benefit from constitution scores above 16, for example. Unless they are shorties, then they at least get +5 on their respective saves from Con 18. But no extra hitpoints.
AD&D is horribly complicated.
So back to Charisma specifically.
Namely you want a reaction score of 15 from the start, which is considered the "friendly" reaction score.
Reaction score is 10 + charisma modifier + reputation modifier.
Charisma modifier is +1 for 13, +2 for 14, +3 for 15, +4 for 16, +5 for 18, +8 for 19, +9 for 20, and another +1 for every additional point until the maximum of +14 for 25. Also -1 for 9, -2 for 8, -4 for 7, and another -1 for every additional point less, until a minimum of -8 for 3 and -10 for 1 (Dwarves only, and only the EEs actually allow to lower Dwarf charisma to 1. Dont ask why, I have no clue, the original AD&D rules as far as I'm aware definitely always allowed Charisma 1 for Dwarves).
Reputation modifier differs between the originals and the EEs. In the originals you get -1 for 8, which is why you wouldnt want to start as chaotic evil in the originals. Again the game treats you like you wouldnt have any charisma at all. The EEs lowered the penalty for low reputation by one step, so picking chaotic evil is fine now.
Positive reputation modifiers start at +1 for 14, then +2 for 16, +3 for 18, +4 for 20. So even with reputation 20 you still would need Charisma 13 to actually archieve positive reaction scores.
OTOH the highest negative you can get in the EEs from reputation is -7, which you can compensate with the +12 from Charisma 23. Which is kind of funny. The originals gave -20 for reputation 1.
How you personally play is obviously your perogative, but I prefer having Charisma 18 on my protagonists.