There's lots of places in the head for oil to puddle. But it seems like an hour is long enough. ???

Maybe the biggest reasons for the variation is oil temperature & levelness of the parking spot. It can take several hours for the engine to really cool down. Levelness side-to-side might be the biggest thing. Get your right-side wheels down (highly crowned street?) and it'll measure low because all the oil runs away from the dipstick.