The gentleman I spoke to didn't actually specify if it was a HTV which they had experienced problems with. He was more just talking about the superchargers and coatings in general, saying that they have had problems with that injection method at some point.
As the common consensus seems to be that it's the older style blowers and coatings if any, are the ones that have the problems. With how far technology has come in so many areas, you wouldn't expect something simple like this to be a problem anymore. And at the end of the day, if it's working fine for you and even keeping things cleaner, then its smiles all round.
On a side note Andy, those valve covers of yours, is that a polished finish on them or some form of ceramic coating, etc?