Some random thoughts

[Wdll]

I have stopped resupplying my artillery when playing against the AI (and considering doing it for the PBEM games too). I am not sure what you mean single player cheating with the z-fire.
If you want to have some fun, play campaign (10 battles) against 3 different opponents, single battles can get a bit boring. Try to get decisive victories all the time.

[Ramm]

Originally Posted by Wdll

I have stopped resupplying my artillery when playing against the AI (and considering doing it for the PBEM games too). I am not sure what you mean single player cheating with the z-fire.
If you want to have some fun, play campaign (10 battles) against 3 different opponents, single battles can get a bit boring. Try to get decisive victories all the time.

The AI cannot deliberately use suppressive fire (z-fire) against unspotted units like us human beings can, except of course with the use of airplanes, and that isn't, strictly speaking, using z-fire.