I think it depends on both. It would be unfair if it was based just on position.
For example:
Imagine that div 2.1 in australia was really really hard, and div 2.2 in australia was really easy.
Now maybe a team in div 2.1 needs to win 14 games to make the playoffs.
But maybe a team in div 2.2 only needs to win 10 games to make the playoffs.
It isn't fair to reward both teams with the same increase in STH.
The same thing applies to conferences within the same division.
Perhaps it is easier to make the playoffs in the Great 8 conference, and really hard to make the playoffs in the Big 8 conference. So I think that the record comes in to play as well as the position.
In other words, it is better to finish 4th with 15 wins and 7 losses than it is to finish 4th with 12 wins and 10 losses.
It also means that every single game throughout the season counts, and that tanking any game is bad for STH.
However, I think the place you finish is still more important than the record.
So finishing 4th with 9 wins and 13 losses will still result in an increase in STH even though the team lost more than half the games for the season.