Heres the jist of it. Ya wanna play with your friends in premade groups spamming dungeons for tomes or xp, thats fine. You just aren't going to get a bonus. The bonus is an incentive to get out of your comfort zone and help others. Some, like myself, spend a lot of time solo because of my playtime being opposite if most of my friends in my fc. Its a good thing the way it is.