A lot of the time I feel the RNG of the quest line as a whole doesn't reflect upon the reward of the upgrade. I mean heck, some people finished the newest one in 30 hours and I know I've run more than 30 hours of Haukke Manor hard mode just for 1 drop. Even then, the upgrade once finished is 10 levels lower than raid weapons and only 5 levels higher than a new Tome weapon, also restricted to coil.
