jimp what did you pack it with? Did you bring clean in before pouring on top of it? I plan on piering the floor in a few spots to help with settling. I have a ton of quickcrete and am going to put about 8 piers down to virgin soil before i do the slab pour.
I used it for fill inside my stem walls. So the foundation (including piers)were in place before I filled the slab area.
I did not think about the need to compact beyond the skidstear placing it, since it filled so well( It was about like the crush run, a lot of fines). I did all the work myself, so, there was about 3 weeks between placing the fill and pouring concrete, that and a couple rains set the fill up like concrete.
I did not use anything else, sand or gravel, before the pour. I did not have any floor cracks outside the control joints (floor was cut into 16'X12' sections and had #4 on 12" centers).
If your fill is like what I got, I would not see a need do anything but pour the concrete on top if you take care in placing.