4th Ed Overrun attacks

[richvalle]

Man, I hate trying to parse rules this close.

Extended assault does say it is like Cav. Though the rules read like it is a singular unit.

Extended Assault Similar to cavalry charge (15.31), an AFV unit activated by a tank leader (including loaded APCs, but excluding tanks with riders) may conduct extended assault from two or three hexes away.

On the other hand Overrun does seem to be plural:

Once the overrunning AFV(s) or cavalry enter the target assault hex,

The only way to get plural is if you move a unit up next to an enemy, it pauses while other units move up, then they all go in together.

I really think the intent is for a stack of units to assault at the same time though I am willing to admit I could be wrong.