That's what I figured. I know that the recirculation is necessary for keeping temperatures consistent throughout the Foundry, but my crush is relatively fine (since I BIAB) which helps get me closer to 90% mash efficiency. I suppose some rice hulls would make a big difference. I've also always squeezed my bag to get the most liquid out of the grain as possible. With a Foundry, I could literally press the bag/basket with a pot lid to maximize the liquid into the boil kettle.Sorry I wasn't specific, my last sentence was meant to say I have used the Foundry yet.
Beer making in anything should however be similar. Crush fine, add rice hulls if nervous about the fine crush, sparge (aka rinse). You shouldn't have too many issues w/ efficiency. In the end you are just soaking grain and getting its contents, no real magic. The idea that a bag makes much difference either way says to me we have other variables going on and super small sample sizes to work off of.