I suspect so yes.
Same as local store-bought WoW gamecards.
The price is set in stone in ZAR.
But I play US. Sometimes I get to buy the cards at a MASSIVE discount due to $ differences.
Same thing with Steam. Because we're working in $, you might get really good deals when the dollar slumps a little. With EA, they support ZAR directly and thus the price is (as mentioned) set in stone, with no possible conversion savings coming into it.

