When the pump is set above the bottom end of solid casing or above the perforations, water will draw down from above until the static water level drops to the dynamic or pumping level, then water will start coming from below. In a rock well or one with no casing, water will come to the pump from which ever direction it enters the well. If the cracks and fissures are above the pump, the pump will be fed from above. If the cracks and fissures are below the pump, it will be fed from below, but only after the static level has drawn down. What is not known is the percentage coming from above and below at the same time until the well draws down to static. Hopefully enough will come from below to adequately cool the motor until the static level draws down, but you can never be sure. Since the motor is on the bottom and the water intake between the pump and motor, only water coming from below will cool the motor. A flow inducer or shroud makes sure the flow always goes past the motor before entering the pump, no matter if the well is top feeding the pump or not. A shroud also works as a centralizer and protector as it keeps the pump/motor from being able to bang against the casing or rock. There are lots of good reasons to use a shroud on every pump installed. The only reason not to use a shroud is if the casing is too small for it to fit, which I consider a well design error.