Never seen a hydro system that cut the flowering time down on a strain - but I haven't seen everything. Have you done side by side comparisons? Me and a friend have run side by side with the same well-known clone, he in hydro, me in soil and flowering time was still the same - although in the hydro setup he outyeilded me due to veg time being quickened ie he got more done in a shorter time - for controls sake I flipped the lights same day as he, though I would have normally waited another week or two.