Also, this would be a good time to make it clear that you do NOT get to choose which specific model you will get. You can only order an "HD-DVR", and DirecTV's system will only note "HD-DVR". You will be installed with whatever receiver the installer has on his truck at that time (90+% of the time, that will be the newest version available, which is the HR22 in this case). Technically, you could receive a refurb HR20 or HR21 or a new HR21 (not many left anymore), but every day that goes by increases the likelyhood that you'll get the HR22.
The reason I point this out is because many people WANT an HR20 because they want included OTA capability, but despite many CSRs putting many notes in a customer's account, there is simply no way to ensure that a specific receiver model will be available. These days, the only HR20s are refurbs, and there are relatively few of those in active circulation (meaning: available to send to customers), and the ordering/fulfillment system is specifically designed NOT to track by model number, because there is no central database of who has which receivers, and the availability of specific models varies from day to day. It wouldn't be cost-effective to try to keep track of receivers at this level, so they don't.
Dozens of people have posted "My CSR *promised* me..." only to learn that those assurances are meaningless, because DirecTV's policy is that "an HD-DVR is an HD-DVR" and so customers get whatever is available, which again is almost always the latest model.