if i press the keys to near perfection right from the start and capture exactly the same as the ai, it still has more units in a shorter time when i already ran out of recruits.
my teammate and i discovered that on numerous occasions, also did i see that on normal skirmish.
1 gog and 1 vault version playing together at 1.0.20.0. also me playing on gog 1.0.10.0 and 1.0.20.0 so i dont suspect there is a bug involved.
we just thought the ai would get a little "help" because of no dragon ai and the overall disadvantage of a "ai" so it seemed fair enough.
after all when you know how it works you can steer whole ai-armies around with 1 trooper like a donkey with a carrot on a stick

edit: just a second ago we finished a match where the ai had nothing left but 1 recruitment centre for a long time. and while pumping out troopers he built ALL (6-8 dont remember exactly) turret emplacements at the same time (!), with AA and lights.
and we can be pretty sure he didnt save this much resources i can tell you that

also on some campaign maps the ai gets a free research on ALL units right from the start on some maps
