What is the consensus of guys here who lift on their plate-loaded stuff? My youngest just started lifting as he hit 6' and we are not concerned about epi-fusion. One of my gyms has a lot of 55lb plates and six on there is not remotely 330 on flat bench. It's harder initially as you have to load at the chest vs. loading from a rack and it's incline, not flat. Please post your 5-rep with flat bench (free) vs. their ISO bench.
He's not lifting much, but I've just started to use the HS plate loaded as he prefers it to me spotting him.
I can lift 30% - 40% more on a plate loaded hammer strength chest machine when compared to what I can do on a flat bench. Not needing a spotter on a plate loaded machine gives you the leeway to really go all out, even negative failure, where it's not really practical to do that on a flat bench due to the help you need getting the bar racked back up. Plate loaded machines are convenient, but they definitely give you a false sense of strength. I use to put 4 plates on each side of a declined bench machine and bang out reps like it wasn't anything. No way in hell I could ever do that much weight on a flat bench.