It looks to me like FFG is trying to keep 2 Loss players from making the cut for smaller round counts. At 40 Players, a Top 8 cut after 5 Rounds could let a single 3-2 player in (same for all the way down to 33 players).
At 45 players and 6 rounds, Top 8 cut might let a 4-2 player in.
I would guess they drew the line like this:
"At 5 rounds of X Wing, we don't want any 3-2 record players making the cut because they only won 60% of their games."
"At 6 rounds of X Wing, we are okay with 4-2 record players making the cut because they won 67% of their games."
It sucks that some players (up to 3?) that win 80% of their games are stuck using Tie Breakers, though, just to keep 60% winners from being put in the cut. My guess is they also assume a certain # of 1 loss, 3 win, 1 modified wins will occur, and are okay with just never letting those players make the cut. Once you get a mod win, you better not lose!
