I put a question on QSI forum regarding the fact that my flats took 25secs a sub to do, to get around 30,000 adu & was this normal. I stated the equipment I was using, at the time, including the 7nm ha filter & a chap answered that it was normal considering the equipment I was using. He has a 3nm ha filter & his take 40 secs each sub. We both use a light panel.
Well at least I know :(