Montbell Stretch Question

If it takes an ounce of 800 fill down to fill 800 cu in, does Montbell measure their loft (to get bag rating) in the streched, relaxed, or intermediate condition. If they measure the loft to get their rating when the bag is in the relaxed position, then it seems to me that if the bag were to be strected there would be more area and the loft would decrease.
How does this work?
I had a 'Stretchy Legs' bag that mountain hardware made- and one that Sierra Designs made, so I familiar with how the bags work. Just wondering how Montbell figures their loft. I am looking at a 30 degree bag and my search shows that owners are happy with theirs. I plan to use this below 30 degrees and compensate with clothing.

Something that specific, I think you should ask MontBell directly.

But suffice to say that reading user feedback over the last few years, it's been fairly consistent that MontBell bags are rated pretty accurately for the "average" sleeper -- as WM bags are rated conservatively. That hopefully will give you a general feel.

I have been reading about them for some time. I have a WM now and am very happy with it. But am considering getting something new to shave some o z's. I think the Montbell stuff is priced better. Anywho, the stretch bags I had before were both synthetic and jsut thought someone might know the tech specs on this. It might be a little critical, at least for some degree of comfort, since I plan to push this bag past the limits.

Head on over to E.T.O. and try one on. Ask for Ian or Bret, they use them and will be honest with you. I get all of my gear from them except this year I'm switching back to W.M. bags.

Last time I was in there was to check on Dave the Wave after he knocked his teeth out on the rocks at the bottom of Groove Tube.
http://www.americanwhitewater.org/content/River_detail_id_1080_#rapid770
I am not sure I would know anybody now.

Please let us know what you find out. Good question! I'm real close to droping the coin on one.

“But am considering getting something new to shave some o z's.”

Something to shave oz besides WM? That’s a tall order. WM uses 850+ fill and Montbell uses 800 fill. Plus Montbell uses a 22% heavier shell.

Right on, but if I go from a 20 degree bag to a 30 degree bag I will shave ounces and possibly save money. So my quest might be to try a different brand and to cut costs, while shaving some weight.