I'm pretty sure this has been said, but the random number generator in BB2 has to be broken. I've seen 1 and 2 nearly half the time and 3-5 a third of the time, and 6 is like a rare unicorn.
I've seen more 2+ rolls that end in 1 reroll 1 almost every BB2 game I've played than I have seen in 4 seasons of tabletop blood bowl games.
When the number generator comes up with a number, it seems like even if you want to reroll the result, it likes to keep the result for the other roll. I've rarely seen anything come up that it needs to.
It also seems like when playing against the computer, the better the player is doing, the worst the rolls get as well. I'm not sure if it is something that is/has been looked into, but I can't believe I would be the only person to complain about this. I see a 67% chance of success and go "Ok, so there is an 80% chance of failure without a reroll." It has gotten to the point that if I see a 67% chance and I don't want to risk a reroll, I don't take it.