That plate is held in with 2 screws? Even if into studs, it doesn't look very secure. I would at least have some sort of leg at the bottom to releive the forces on those two screws.
And as far as holes in the roof, how many sat dishes are mounted securely in roofs all over the world that don't leak? The big thing is to seal and never remove. I have one foot pad still in place from an early pre-direct dish. I have two securely with no leaks on my roof.
it has 3 lag bolts holding it onto the stud. I will probably add another 2 but I was certain that it wouldnt move, which was proven during hurricane rita this past year. Plus its like a 3/8" aluminum plate, I guarantee you that it will not sway
just put the dish directly on the roof, the installer will seal the lag bolts the best he can, then there will be no question if it is mounted correctly.