I.e.
2nd place finishes on 76 points.
3rd place finishes on 75 points.
4th place finishes on 72 points.

What is the crucial figure here? It is 73 points. Basing any calculation on 3rd place figure of 75 points is irrelevant.
To get into the Play-Offs the figure is 1 point above 4th place. So giving the 4th place plus one point situation for
each season and then taking the average over 10 seasons is appropriate. It is what the aim is.
We shall ignore goal difference because the options are too numerous.

So you can clearly see that the most important figures are :-
1 point more than 4th.
1 point more than 8th.
1 point more than 23rd.

Basing calculations on the number of points that 3rd+1, 7th+1 and 22nd+1 amount to is irrelevant.