I can't remember exactly how it worked, but yeah there was a time when teams got an advantage in the play-offs due to league positions.
Was it not 2nd vs 5th (home leg only)
Then 3rd vs 4th (home leg only)
Then 2 winners in the semi final, highest place team at home.
Then a two-legged final against the team that finished first?
Could also have (or as well as) been top 2 to semi finals, 3rd vs 6th & 4th vs 5th home legs only / points advantage.
I feel like that was changed, because the team finishing top had a long wait for the final, when others were racing.
I'm sure the season(s) they had a points advantage to the higher placed team, it only occurred in the semi finals. The finals have always been even between both teams.