I haven't had a summit, but did anybody actually use the ability to fold the OG diffuser plate often? With my Primo Oval XL, I never had to 'add' charcoal even on 18 hour cooks, I just put the right amount in up front. It was too much a pain to move the food/etc out of the way to get in to add charcoal, even if the area was open. I'd imagine it would be the same on these, and you'd have to take the food off the grate to even get to where the diffuser was, at which point you might as well just move it too. Less moving parts to fail this way, and easier to clean. That said, perhaps there's some functionality with the folding diffuser I'm missing.