I'm going to take a guess (hopefully somewhat educated) that there's truth to Cael's estimate. I suspect the coaches are at or around the wrestling room all day, and guys may pop in and out throughout the day, so the may be on the mat a bit during the day. I think during practice, the coaches are highly interactive, and from what I've heard in the past, Penn State's practices are very free-form where guys are just working on things with each other. Keep in mind that Cael has been an innovator around "play" wrestling, where guys are wrestling around 70% and just working through a variety of positions, trying different things, taking turns. You see a lot of it today when guys warm up, which is probably at about 40-50%. You want to see Aaron Brooks get taken down? Getting taken down and put in bad positions is all part of it, learning how to deal with the bad positions (both as the offensive and defensive guy). I'll bet 100% wrestling is extremely rare, and if it does occur, I'll bet it for short bursts only. Point is that I bet all coaches are on the mats throughout the entire practice. Not like my coach who stood there with a whistle and screamed at me!
Then, you've got post-practice. Some guys may hang around. I think that's the point where the PSU guys can practice with the NLWC guys. So keep in mind that Kerk can't practice with Snyder or this new giant until after practice. My guess is that Cael is mixing it up with Kerk throughout most of PSU's practice, and then he's hanging around mixing it up at the post-practice as well. This applies to Cody, Casey, Kennedy, and Varner as well.
I don't know this for fact, and maybe someone can correct me, but I BELIEVE Cael was an innovator as far as coaches largely practicing with the guys. Nowadays, it seems like this is commonplace at all top programs. I'm more confident that Cael was an innovator in the free-flowing unstructured practices, as well as bringing fun into the mix (e.g. Dodgeball, spikeball).