How do Overruns work ?
Rule 6F (Movement – Overruns) states that fatigue hits, terrain, supply, and support modifies combat factors for the odds calculations. The rules for artillery (Rule 12B (Artillery – Artillery Units)) describe the effects of terrain (fortifications are a type of terrain) on each type of artillery unit. It also stipulates the effects of movement on combat factors and since overruns are movement these apply. Thus, artillery gets its multiplier based on the type of fortification (or lack thereof) and halved for moving (if applicable). Artillery must also have sufficient non-artillery REs to count their full combat factors since this is a form of support (see Rule 12B). We now turn to assault engineers (Rule 13E), flamethrower units (Rule 13F), and siege engineers (Rule 13G). These units get their combat factors modified based on the fortification type and whether they are attacking or defending. All of these modifications are applicable in an overrun situation since they are terrain based
