For those of you who wonder if pouring the decking immediately is a good idea, I offer this photo of my build. The backfill was done two weeks ago. The original level of the dirt was just above the coping. The dirt settled this much after only one rain event. Now I know why my PB wants to wait 6 weeks to pour the deck and encourages the use of sprinklers in the meantime. They are coming back out today to do another layer of backfill. Otherwise all plumbing and electric are finished.