Up until this point for the MLU, there have been only three games involving both an East and West coast team and all have been the MLU Championship game hosted in Philadelphia.
These matchups appear to have been chosen based on the final division standings at the end of the 2015 season. This is similar to the schedule format that you seen in the NFL. The top team in the East will play the top from the West and same will happen for the bottom two teams.
In all cross-divisional games, the Western Conference is winless (0-3). This will mark the first time that an Eastern Conference Team will travel west for a matchup. Also with New York and Portland both playing a team from the opposing conference, the Philadelphia Spinners will be the only remaining team in the league to not play a cross-divisional game.
According to the original expansion plot, outlined in 2013 by former commissioner Jeff Snader, the league's move to cross-divisional games is a year behind schedule. With this cross-divisional move also not including all of the eight teams it would be fair to assume that the expansion plan may be pushed back another season as well. With the goal of expansion being in 2017, it might be 2018 before expansion (note the expansion locations at the time were NJ, Toronto, Pittsburgh, Chicago, Minneapolis, Denver, and San Jose).
Nevertheless, this move is huge for the league especially in response to the AUDL's new additions taken from the DC Current. These two games, that will be included in the 10 game schedule, offers new competition and excitement to fans in the respective cities.