The AI is truly terrible, me and my friend play 2v2, and when looking back at replays vs a Hard/Expert, (which we have fought our way upto) they gain twice as much manpower as they should be.
It says +270 for them, but we worked out they are getting around 600 manpower per minute where ours stays the same.
Tried uninstalling Eastern Front and the AI is still ridiculous, nothing changed so will probably uninstall the whole of COH and reinstall.
You might be enjoying not winning now, but when you have to squish yourself into a corner and fortify your base before slowly pushing back you will get well and truly pissed off with this.
As for stats, Expert AI gain 3 times the amount of manpower they should be getting.
I hope you are patient