The difference between 5th and other places is often very narrow. I checked 20 leagues in USA D.IV (1-20). In 23 of 40 conferences, the 5th place team had the same record as another team, and the placement was decided on point differential:
9 teams, 5th and 6th tied.
2 teams, 5th, 6th, and 7th tied.
8 teams, 4th and 5th tied.
2 teams, 4th, 5th, and 6th tied
2 teams, 3rd, 4th, 5th, and 6th tied
Add a possible imbalance between the two conferences and giving a team a chance for 5 extra games and possible promotion, sitting home twiddling their thumbs, or 3 extra games and possible relegation, the decision process is somewhat capricious.
With only 1/4 of teams relegating, BB is going to have problems with bot build-up, so they should really use the playoffs as more of a process to rank teams, especially between the two conferences within leagues, and reduce the chance for the lucky playoff run for promotion.
Possible formats:
6,7,8 from both conference play in mini-league of 5 games to determine 11th-16th places. Regular season games count 1, mini-league games count 3.
3,4,5 play in mini-league of 5 games to determine 5th-10th places.
1,2 play two rounds best of 3, to determine 1st-4th places. Or possibly make final best of 5.
4 through 8 play 5 interconference foes, to complete 18-game home-and-home season to rank teams 7-16. Games against top 3 teams in either conference wouldn't be used for final record for placement.
1 through 3 play 3 interconference foes to complete 10-game home-and-home season to rank teams 1-6.
5 and 6 play best of 3 to determine 5th and 6th. 1 - 4 play two rounds best of 3 to determine 1st through 4th.
Best of 3 series could use Tues and Thursday, with Saturday if necessary.
Some format that uses inter-league play, and international play for 1st division teams.