It's all good... So far at least.
I called the special number at about 7pm Pacific time this evening to upgrade my 921 to a 622. I was on hold for about one minute before being connected to a very helpful CSR in Virginia named RJ.
It took about 15 minutes to review the terms and do the upgrade. He offered an install appointment in 21 days from tonight. I chose April 25th for my convenience. If I call back in a few days he said I should be able to get a UPS tracking number for the shipment.
He verified that my $8.99/mo locals plus super-stations would continue, my $84.99 AEP and $9.99 HD pack would be replaced at activation with HD Platinum for $99.99. No DVR fee.
No lease fee because the 921 was and the 622 will be my only receiver and therefore the "primary" receiver.
Total monthly charges go up by $5.01 and I get my HD locals, ESPN2 HD, Universal HD, and 15 VOOM channels beyond what I get today. That seems like good value to me, particularly when I'll get any future additions to the HD package which I wouldn't have gotten with the 921.
From the reports I've read here over the last couple of months, the bugs in the 622 are pretty limited and tame compared to the 921. It is painful to get only $200 back against $489 cost for the 921, but I don't need two receivers and I don't think I could easily sell the 921 for more elsewhere.
I currently have a D500 for 110 + 119, a D300 for 148 (minor LA locals), and a SW64 switch. He agreed that the upgrade would require a D1000 plus the existing D300 for 148 plus a DPP44 switch to handle four slots (and that the existing legacy LNB on the D300 would have to be replaced with a DishPro LNB). He put a note on the install order to make sure the installer will bring out the DPP44 switch.
He correctly warned me that there is an 18 month programming commitment with a prorated early termination fee and that my account will be charged $299.99 when the 622 ships and that the $200 will appear as a credit on my account after Dish receives my returned 921.
Before ending the call I complimented him on how smoothly the upgrade had gone and his reply was "That's all we do here all day long." I'm very impressed.