Going from any of these items to 4 requires an extra special leap of faith. I personally see anything short of a full 4 as essentially being office work theater.
Our company operates as a 4 tier and I've been here for going on 7 years now. We still have to get on a daily standup call at a fixed time every day, and I still have to participate in other scheduled obligations (mainly tech calls with customers), but the rest of the time is mine to allocate as I see fit.
Also, there are consequences with "no fixed hours" that lots of humans are incapable of dealing with. The amount of discipline it requires to manage this freedom is not insignificant. This said, I am not against multitasking. If you can have something rolling while you get your work done, fuckin awesome. I don't care. I am more worried about the individual lounging on their couch, halfway through a 6 pack of IPA getting in some of that game of thrones re-watch, while the rest of the team is mopping up a shitty merge to master wondering where that individual may be at 11am on a Tuesday.