Screwy fire results in Waterloo

[Havoc]

Playing the Battle of Waterloo variant 3 (Prussian arrival unknown) and am playing with the optional rule for fire.

The results of fire are screwy. Skirmisher units with 150 men are getting "no effect" on battalions in column in the open at one hex. The majority are missing. Infantry battalions in line at one hex are inflicting 2-6 casualties.

I've used the fire optional rule to balance results in all the other games I own without problem. This seriously impinges on the British ability to hold the line since their defensive fire is hugely ineffective.

Is this something to do with the latest update, or just with this scenario?