Sorry, but you missed what Jim was saying.
The HD channels are mirrored to the SD channel numbers for convenience to those that do not what to go to the 9400 block to see the HD channels.
So TNT shows in SD on channel 138. then channel 138 shows again with TNT HD. TNT HD also "lives" on channel 94xx.
HBO, HGTV, Food Network all do the same thing.
The lower channel number HD mirror can be disabled if you don't want them there.
BTW a "mirror" of a channel takes virtually no bandwidth. It is a signal to the receiver to put the same program stream on channel x and y at the same time.
See ya
Tony