Apparent duplicates are not, they are just mirrors (copies) of the "real" channel mostly for convenience, putting groups of related channels next to each other, or allowing you to tune your local on its local channel number instead of a random 4 digit channel number.
You can turn off the mirrored low channel numbers (100-499) but not the original numbers (9418-9599 or so). I prefer the low numbers because the grouped by type and provider and not by when they got added.
I cannot, however, turn off the high numbers except with locks, which I do not like. Locks have caused problems with old recordings made before the map down, like on VOOM.
I do use preferences in the favorites lists, but I also like to use the All HD default list starting at 385 and working down. That gives me 5 pages of 7 lines each for all the premium channels in AEP, which will last until they take away the loyalty and receiver credits.
Yes that is right about info+info to see the satellite of any live show. It does not work for recordings.