Propellant lots etc:
It's not necessary to have PGMs to compensate for such variances. It's been standard procedures with several MRL systems to shoot one rocket, observe with radar, then self-destruct the rocket (timer) in the air in order to prevent that the following rocket salvo with corrected aim loses the surprise effect.
It adds a few seconds and is not very efficient with large rocket calibres, but it works.

There's also a trajectory correction system with which the launcher simply aims too high and the trajectory correction module in the rockets gets radio command to deploy air brakes at the perfect time to negate the distance error/dispersion.


Divisions/brigades:
It's been accepted in Europe since the Division 59 (a brigade-based design) that brigades are the way to go. The Americans learned the same in WW2 and re-learned it after the Pentomic excursion (maybe after ROAD, don't remember ROAD details now).

I'm still struggling to learn whyTF the division has come back to favour with so many people. It's obvious to me that we should delete the division level, not the corps level.
Brigades might actually be too large already. A very small brigade (two reinforced battalions worth) might be the way to go (=full circle to early 50's). We need very agile formations, and we've got much to do till we have them.