What I do with my line is of not their responsibility to manage. I don't understand the non-real-time aspect you're talking about, but as an end-user I don't discern between traffic and I don't expect my ISP to either. If I'm doing 20 gigs a month of torrents or 20 gigs a month of downloading ebooks, how much difference does it make to their network stability and capacity?
Real time services are things like YouTube that require constant bandwidth and won't be usable if it gets slowed down.
Non-real time services are downloads like torrents, news hosts, HTTP downloads and will get managed before real time services as to not affect them.
Because of the high cost of bandwidth in SA all the ISPs have to heavily contend users to make their services affordable. An example of contention would be a ratio of 1:50, so for every 50Mbps that the ISP sells they only buy 1Mbps bandwidth
Some ISPs offer accounts with lower contention ratios, but this comes at a price, a lower contention ratio will translate into more overall bandwidth available per user.
To give you an idea of what bandwidth costs in SA, here's a breakdown of what it would cost to provide a single user 1:1 contention for a 10Mbps ADSL connection:
Telkom IPC access: R1400/Mbps/m X 10Mbps = R14000/m
International Transit: ~R700/Mbps/m x 10Mbps = R7000/m
Local Transit: Depends on the network being used, I don't have pricing for this.
Total: R21000/m+Local transit
Prices are ex vat