All my cars have been petrol and this (S4) one's oil gets blacker, quicker than the others. Like you I have a dipstick, so that's how I know. Other owners, perhaps never see their oil before the next change? My previous car was S4 2.7 (Twin Turbo) and remained "browner", longer.
This is my first supercharged engine, could it be that there is more boost more of the time than a turbo perhaps?
Supercharger has more boost at low revs compared to turbo. Just a thought. Or is it another by-product of Direct Injection (like the carbon build-up on valves)?
I change my oil (fully synthetic) every summer, before I drive to France on holiday.
The later CREC Engine like Dippy's S5 above has a clutch on the supercharger, that will be to minimise emissions I would think, wonder if that would make any difference.