There are a few reasons - it makes us really hard to classify the traffic is external DNS, VPNs etc are being used to use services like Netflix/ Hulu.
Looks like some guys seem to be all good and others not.
We can only look at so much data within our network to troubleshoot but if external DNS and third party systems are used to bypass whatever country restrictions. We try and see streaming sites/ sources that are locally available unshaped as much as possible.
I'm sure that if Netflix does actually land in SA and allowing sign ups locally we'll see the traffic unshaped.
I'm sure at least 90% of the Netflix users here use Unotelly as their DNS provider, as do I. Shouldn't that void your argument regarding external DNS and wouldn't that point to a different reason for the degradation in service?