Sorry, I am going slightly OT, if it's consider intrusive, tell me and I will shut up (and maybe move to a new thread).
Your assumption isn't random at all. Firstly this is simply what quality means and secondly that's what it says in the Rawpedia:
[...] higher quality at the cost of processing time.
@agriggio's and @Morgan_Hardwood's statements contradict this. Maybe a warning in the Rawpedia, that it is another tradeoff between quality and NR, not quality and processing time (which I don't care about), would be in order?