Top ranking universities to study engineering and computer science at in South Africa

No. This analysis is wrong. It is premised on really bad foundations. For one, URAP is not a reliable ranking system, and larger universities are favourably biased since URAP evaluates, among other things, the number of publications. Paper mill universities (which SA sadly has many of, particularly in the lesser credible ones) thrive on this ranking, and I've seen plenty of hopeless drivel being pushed through questionable journals.

No, no, no. Do not base your future on this analysis at all.
How did you average rankings (lower is better) and scores (higher is better)?