I have the exact same problem with my VIP722K. Only I get even less time back when I delete a program. An hour program, when deleted, usually gives me 17-18 minutes more on available space. This morning I deleted 2 hrs 4 min. and gained only 34 min recovered space. I have talked by phone to Dish techs, and they always tell me that no one else has this problem. They, too, suggest that I wait a while. Well, nothing changes while I wait. I've now been told to wait 14 days and see what happens. Meanwhile, I'm getting close to 0 hr 0 min available!
I do show that there has been reported issues, however, it was reported for the Hopper system. I would be more than happy include your information about your 722 in the report. Can you send me a Private Message with the phone number and 4 digit PIN on the account? Also in your Private Message, please include your receiver number, smart card number, software version, and the hardware ID number. Thanks!