Alec's dishwasher videos are based on some rather primitive dishwashers. For instance he talks about his test unit not flushing out the spray arms, but Bosch/Siemens filters the water going to the spray arms so it wouldn't recirculate dirty water anyways. Same deal with the prewash. Bosch uses a turbidity sensor to determine how many "prewash" cycles to run and when to reuse the water, something his test unit very clearly does not.