I've got a Dish 6000 with a Dish looking at 110 and 119, and a second dish looking at 148. The two cables coming out go to a SW 21. It is NOT a dish pro switch 21. To upgrade to a 921, can I just get another SW 21, and connect two more cables to the LNBs (each one has two taps, only one used) on the two dishes, then run another RG6 cable down to my living room? Does the 921 require dish pro switches? If it does, then do I have to get dish pro LNBs and switches????