Unless things have changed since yesterday when I talked to DISH CS, you can only record TWO shows at the same time and simultaneously watch a PRERECORDED show. You can't record 3 at one time simultaneously. If you need to do that, you could use an ota receiver box and record to a standalone DVR or VCR by splitting you incoming OTA signal before it hits your DISH box. OR, you could add another DISH two tuner DVR for about $12 / mo. more on a two year contract. This is what I'm considering so that we can record three and watch one live simultaneously. We do also use and OTA antenna and have merged the OTA signals/channels into our program guide.
Also, I was told that the 722 only has ONE HD tuner and one SD tuner, not two HD tuners. But then, maybe DISH CS is feeding me the wrong info......