Yeah, ain't that the truth! Only thing is...as you know, customers will get the impression that there is no moss on the south side and inevitably ask if you can just spray that side of the roof (the answer is always No). Guaranteed if you see it on the North side, it is on the south. I've had guys bet me 1/2 the roof clewning fee that there was nothing there only to have them come out after spraying to point out the south side absolutely peppered with white moss on the shingle edges. Happens every time!