The floater makes absolutly no sense to me. Yeah I see that it is attaching the upper and lower frames together, but you make a point to say that it shouldn't make contact with the floor. Since you are finishing out the top with ply why would it matter if it makes contact or not? The ply is gonna distribute the weight to all points beyond the 4 corners....
IMO the "floater" looks like an after thought of someone that didn't plan ahead....
