Tbh Sinta Silver is only about £18 from the stealer anyway. Why use anything else. 
If it meets the spec, wheres the problem in a cheaper brand?
Quite true.... BUT as a comparison, Supermarket fuel meets required specification, but can create running problems on all sorts of vehicles, petrol or diesel... and I certainly wouldn't put it in my Golf.
Anyone remember the Mayo problems with Duckhams Oil? regarded as one of the best, but was responsible for killing off many engines long before there time
Spec or not, you get what you pay for, be careful what you put in!
Thom