DVR Chatter

So I've been reading up on settings for STB's and stuff because of what I found happening to me and to others as well. And lots of opinions on how to resolve it. I usually get pretty good ideas here.   WAREAGLE I think you'll recognize this from AVS forum.

I am using HDMI for the first time with my new DCX3400 DVR.   The DCX3400 displays the format it is putting out, like 1080i or 720p.  Having it set to 1080i on the  box, (my TV is actually 1080p), when I turn the TV off/on...there is a brief 'handshake' that takes place, and the box immediately goes to 720p. Actually, I don't think I would know if the box wasn't displaying it so.  But I change it back to 1080i and it stays there until I turn the  TV  off/on again. Then it was back to 720p.

I tried  'native' mode on the box settings.  Then box changes back/forth between 1080i and 720p, depending on what station I'm watching. 

So I tried this , and it seems to be the solution:  I set the DVR to 1080i (like before),  but THIS time, on the DCX3400, there is a list with boxes that you check where you tell it what formats your TV supports. Before it had several choices, most of them checked, like 720p, 480p, etc. It has THREE choices for 1080i.   1080i 24, 1080i 30, and just 1080.  So I unchecked everything except the 1080 choices. Now it stays on 1080i no matter what station I watch.   It seems to be what solves that.

Anyone heard of that ?  Or other solutions ?