[cbo]

Its a partly a Troop Quality/Country Training issue. Assuming the time is May 1940, I bought at 3700 pt German force and had the AI buy the Belgian force.

With "Training" on, the Belgian AI bought 250 units, with "Training" off and Troop Quality=70 for both, the Belgian AI bought about 175 units.
The AI was buying basically the same kind of units, just less of them, as the price was higher with "Training" on.

However, even if Troop Quality is the same, the Belgian side buys more because many of the units they have a are generally cheaper, reflecting their inferior capabilities compared with the German ones.
This seems to be particularily true if you have "AI Tank Heavy" on in the preferences, as the Germans have more expensive tanks, generally, than the Belgians.

Claus B