... having 6 teams doesn't reduce it for the rest of the eastern teams.
Currently, with USC/UCLA 8 hosted games means only about half of the Big 10 teams travel west per year.
Add UO/WA and you're up to 12 hosted games, meaning nearly all Big teams travel west once every year (though switching locations).
Add two more beyond that, and you're still at 12 hosted games, but between 6 locations (5 actually counting USC/UCLA together, and if it's Stan/Cal as the other pair then it's really just 4 locations.).