I'm sure that it's possible to grow higher, but a lot of phenos start decreasing their growth with the heat and I've read in a few books as well as from experience that once you top 85 it starts to stunt growth. I'd bet that auto have a natural higher tolerance for heat. ll I know is he's pretty stunted and that's something I've known that's stopped plants from growing. A lot of strains are bred for growing in Holland/UK and are pretty much fine tuned to that environment. The ones that do the best and are chosen grow the best in those temps, so it's possible ( I don't know where you get your seeds or w/e ) that you are working with a strand that really tolerates heat and I'd like to know what because I have a bitch of a time with temps in the summer, but almost everything I've read has pointed to 70-75 as optimal and 85 as a top end for growth. Someone else said 92 they stop growing, maybe that's the case, either way it's a possibility. I'm always open to learning I'm not claiming to be an expert but if I see something that I've read repeatedly could possibly be the cause I like to try and help out.
Really I dont know but I have had 2 full crops done and I had some haze and blueberry and the haze pollinated part of my blueberry and I have been growing them I see no stunted growth I have alot of air moving around I just cant keep the heat down. I just looked at them b4 I come on here and it was at 94. I also keep everything watered pretty good. I just havent had no problems with the heat other then I have to water them alot. Now I guess like you say other strains may take the heat better then others. I hope I never see any of them kinds of stains till I get my other room set up....