I use them, and ideally ^ is correct. I am able to squeeze another tray of five gallon pails in my flowering space because of the mover(s) so I got lucky. It was tricky to create/find the sweet spot I used my light meter for 10 minutes and got it. Thats five more plants cycled for me with one less light. literally, I shut off a 1k light for this trial.
the pain in the ass mover saves me about 15 dollars in power, a little ac. But as stated my lights caress the tops of my plants with each pass sooo.....