I have a one line description of this in our users manual but do not mention it on our site. This is because I has not seen any positive benefits from the little experience that I have with it but do not want to discredit it either.
Perhaps if someone were to post some actual comparative data showing how well the results improved over standard zapping vs plate zapping with all other conditions being equal, then I might see the value.
My point is that I see where it is recommended to plate zap for 6 to 8 hours a day but regular zapping is only for 1 hour or so a day. On this basis I would expect to see an 8 times improvement with nothing on the plates. How much difference does it make if you put the slides on the plate. It could be that the slides actually reduce the effectiveness of the zapping in some cases.
Like I said, I will have to see hard statistical data based on equivalent conditions before I am convinced.