I don't think I am paying extra for HD. I know that the HD Platinum gives you a few extra channels that you may or may not watch. I certainly didn't watch them. As far as you seeing duplicate HD channels, are the duplicates way up there in the 9000+ range? I believe that is the actual location of most of the HD channels and Dish nicely remaps them to the same channel numbers as the SD station (Are you listening? Comcast!).
I just recently downgraded from the 250 package to the 120 package and here is what my breakdown looks like:
America's Top 120 W/Locals - $39.99
DVR Service - $6.00
DUO DVR Receiver - $17.00
HD 120 Free - $0.00
Showtime - $13.00
Service Plan - $6.00
You might call them or go to online chat and ask about it. I'm not really sure how the DVR charges work anymore. It seems like they upped the price on that from what it used to be but only charge for one now.

They used to charge $5 for each receiver and $11 for DVR service. I guess it works out to be about the same.