[Mobhack]

If you think the advance is too easy - then use the "view map" function to reshape the battlefield to make it more difficult for yourself. In particular - you can reduce the battle length, manually move victory hexes to the AIs advantage and so on - for example you might increase visibility if the defender is say German, and so he can make use of his generally better long ranged tank and AT guns. Or you could give him more points by say buying a load of trucks that you sit on your table edge. And as far as I recollect, you can change map size at this point as well - attacking on a narrower frontage gives the AI defender a higher ratio of defenders per yard.

But reducing the time is by far the easiest way to make things more difficult since you will have to press on, rather than having the luxury of time to methodically take his defence apart.

So - you have the ability to make it more of a challenge with a few minutes work.