I've used existing dishes as long as they werent bent or messed up in any way. As far as using used equipment, I get sent out of the shop every day with remanned and used LNB's. If you are leasing your equipment, chances are your receiver(s) are also remanufactured. The dish kits are new on installs, however. But at any rate, I don't see what difference it really makes. When you are getting upgraded, you are, in effect, swapping out dishes, and you really dont need a 500 for that wing dish. But I guess you are the customer, and you are always right.
However, if the 300 was really old and crappy looking, I could see your point.
There is a difference between remanufactured and used. A lnb that was installed in 1997 and got reused is not remanufactured is used and any tech that installs it as reman or new should be fired...........