AM i think Gian needs to be a bit careful here with priority boosted. If the boost or the experience is not where it should be consistently, then you guys might be in very difficult position. I dont see a problem with trying something new like this, but ultimately the experience for the end user needs to be spot on.
Ive been in the Cellular world a long time, retail etc, and from a business perspective, if you provide a product or a new product and it falls short of expectations, then you are setting yourself up here. You have to carefully plan things around consumer needs, what they want, what they expect, value for money, service and many other things. In theory, packages below R299 as i said, should have maintained double data on a shaped package in the event of strain, while above R299 gets a premium experience, but within limits of course on a user by user basis, rather than an entire network.
If you take user A and he abuses the free data, then there should be a team in place to monitor this sort of usage behaviour on an individual basis, rather than collectively looking at how much strain the network takes, and then shaping the entire user base. Just my 2 cents on this, as im still one happy client who has had a good experience overall from service to the network.