Pretorius is in fact a bowling all=rounder - while Andile is more of a batting all-rounder. To consider their performances one has to go to their performances on provincial level and see how they do perform in the shorter versions of the game both in batting nd bowling:-
Batting in 50 over games
Andile Pretpris
Average 26.42 12.33
Strike Rate 87.38 106,73
Bowling in 50 over games
Andile Pretorius
Average 31,46 25,05
Economy 5,53 4.01
Batting in T20 games
Andile Pretorius
Average 11,10 14,00
Strike rate 115.14 136.58
Bowling in T20 games
Average 25,32 20.70
Economy 8,48 7.68
The situation is that Andile played in 100 50-over games and 91 20 over games - while Pretorius played in 18 50 over games and 18 T20 games, The sample is big enough to give an accurate reflection of how the two players perform on a comparison basis.
Andile came out looking much better in batting in 50 over games - but in all other facets of the game his performances were worse than that of Pretorius, I would rather strengthen the bowling and batting combined and in all probably play Pretorius at 8 and Mulder at 7 in both ODI's and T20I"s ahead of Andile.