I don't know why people are complaining that this update will allow power leveling. It's been here since the beginning, you just have the R50 in the party. If it is just the R50 and the lower rank person there is no SP loss and only a minimal decrease if you add more people to the party.

The party's SP isn't dependent on highest rank in the party like FF11. Unless that changes in the future, it will still be more efficient to PL with the R50 in the party since they won't have to wait on the lowbies to claim first.