[Imp]

Okay now I am completely confused both South Africa & Rhodesia have OOB's Rhodesia ends in 1980 as it ceased to exist but that covers your time frame. So why are you looking at Red when you have the correct OOB's?

If your saying South Africa buys to much armour either set them to human purchase & buy what you want for the AI.
or
Try modifying South African OOB removing most armour formations & see if that works. Need to test never tried.
The game should have a backup OOB to restore the original but make a copy before modifying if you like.