>>2718The way reinforcement/combat width works in HoI3 is that only a certain width of brigades will be able to fight in a battle at any given time, and if there's space in there you can have an hourly chance of getting reinforced from any brigades on standby. Large amounts of troops on a single province or a single battle will result in stacking penalties, but there are a few edge cases where stacking penalties and reinforcement chances are rendered moot. Those edge cases lie on absolutely massive doomstacks, massive amounts of generals, massive amounts of small-width brigades, or massive amounts of province sources involved in a single battle.
Usually you don't have enough manpower or available generals to approach those edge cases unless you're one of the big three gargantuan nations with practically unlimited power. The USSR and China are particularly egregious with this since their AI loves to use tons and tons and tons of militia and basic infantry brigades along with an actually filled general roster.
The scenario-generating Random HoI prevents the majority of these issues by making sure that nobody gets too too powerful until the late-game stage where you have 1984-tier alliance blocks going at it full force on 8000km fronts.