No, everyone pays the same, though there are weekly and monthly season tickets. The pricing appears to be a balancing act because they do not wish to be seen to be competing with the mini-bus taxis.

Interestingly the prices for the commuter services (stops along the way) are much cheaper - e.g. R21 from Sandton to Rhodesfield which is 9/10 of the way to ORT. I believe those coaches are more tightly packed with seating (and only their doors open at the intermediate stops). So the idea seems to be to keep the Sandton/ORT route more exclusive and geared to travellers who would otherwise shell out several hundred rand for a taxi.

Will be trying it on Thursday and oddly I'm quite excited!