Stormlord combo in mech assault

So, I think I've discovered a spicy combo.

Stick 2x6 ogryn in a stormlord in mechanised assault. Roll up to an objective, jump all the guys out, pop the reroll strat on one squad, shoot 36 S5 AP-2 shots with +1 to wound and full rerolls to hit and wound. Then shoot another 36 shots without the rerolls. Then end of opponents move phase, jump one unit back in with the stormlord's ability, then in either their charge phase or end of turn jump the second squad back in as well. And do it again next turn.

.

This does 21W to a T10+ 2+Sv target, or kills 28 space marines, assuming an exterminator or hellhound buff. (Not including the stormlord itself)