Are you pushing with your legs/putting pressure on your upper back (like a flat bench press)?
Or do you not engage your legs at all?
I've been unable to settle this for myself. I've been doing it with the legs pushing but I feel silly as hell with my ass in the air and question if I am even still pressing from an incline. If I don't use my legs, I am significantly weaker* and also feel like I just can't push out reps as well (entirely possible I just have to spend more time on the movement and get more efficient at it.)
*Which brings me to my next question- what is your strength deficits between flat and incline presses? I have flat benched 230 but 160 on the incline is challenging if I don't use my legs. Of course if legless is the way to do it, I will just work my way up - but part of the reason I have been doubting the setup and experimenting with using the legs is because that gap seems a bit big...