[Mobhack]

A few points here or there won't make much difference. Several hundred may. You will need to decide as its your scenario.

The easiest way is simply to remove excess arty (which includes ammo units, remember!) from the side that is being penalised, until there is no overload awarded.

Or perhaps, add some more troops other than arty to the player with the excess arty, till that goes away. The excess is based on the excess proportion of artillery points to others in the force.

Or, since you are the scenario designer - use the editing tools to reduce the points cost of the artillery till the overload goes away.

So there are several ways to skin the cat open to you as a scenario designer.

I am considering not using artillery overload in stand-alone scenarios though since scenario designers seem to like heaping on the excess artillery for some reason.