When i want to play quickplay for certain rewards in solo or fireteam ops i cant change difficulty. and its just locked at C tier. i cant get rewards if its not above b. i also cant add modifiers. also i played through battlegrounds oracle 5 times at grandmaster. it said the expected tier is tier A. i played though dusins of times killing all enemies, all champions and complete. only c tier. is there a objective i'm missing like there is in solo ops? the only way i could get A tier was to add a bunch of modifiers when its already at A tier, and farm champions at the end of the bossfight. an unstoppable and barrier champion spawns regulary at the end of the bosses life. i had to farm untill i got enough points then i could finish off the boss. seems like killing the boss and completing the activity doesnt add any extra points at all.