Hi
The strategem Ambush costs 10AP, which allows the defender 2 ambushes and the invader 1 ambush.
The commentary tries to clarify the rules without changing them.
DBMM1.1 from 3rd Nov state:
"
Regular allied commands and commands whose general is lost, is in ambush or has not yet arrived from a flank march or delayed arrival; or that are broken, or that are a Concealed Command not yet deployed, dice independently and are not currently included in allocation or averaging or exchanges.
"
So hopefully that should fix it.
neil