My buddy ran into the same thing down in Bakersfield, his old super told him "let the mud tell you when it's ready" and he pretty much rolled his eyes at first. Couple weeks later he was fighting a hot load and the guy just stood there watching the bleed water instead of hopping on it. He said once that sheen showed up and the water started pulling back, the trowel just glided and he stopped getting those little drag marks on the edges. Now he won't touch a slab till it talks to him, swear it saved him a call back on a driveway last month. Those old guys don't say much but when they do you better write it down.