On top of that tipping is rather silly, I mean we assume it's because we are giving someone a tip based on their service to us. Except if we are tipping on the 10% scale of things, you could go to an expensive restaurant where the waiter is rather crap, but you still end up giving them 10% or 8% or whatever and that comes up to say R50 to R100.
Whereas say you go to a rather decent but cheaper place and the waiter is really good, so you decide to tip them 15% but because the bill is only R400 it's only R60 to that waiter, if you did it using the 10% rule it would be R40?