I thought I had made it clear in my last couple of posts that I clearly understood the difference between movement and sitting on my butt in the cold? I know there is a major difference there and I am not disputing the fact. My comparison was with wearing what I have, WHILE sitting idle at camp last weekend and not being cold at night, in approx 20-25' weather with very strong winds. I will just have to experience the difference between 0, 15 and 25' then because I generally don't notice the difference unless I'm doing something not-so-bright like taking out the trash in gym shorts and a t-shirt when its 15' and snowing. The second comment was in regards to replacing any existing layer with something warmer, if I did that than I would indeed overheat while on the move so it needs to be an addition, not a replacement is what I was getting at.
And I am quite tolerant of the cold. And I don't mean that in some sort of manly 'hah this isn't cold at all! while I get frostbite on my feet' sort of way. I literally mean it in the way that it has to be pretty cold for the weather to beat my natural body heat, even when sitting still (but especially true when moving). And if I have been moving it takes a while to truly cool down let alone get cold. Though I do agree with your sentiment of the real origin of the word 'frigid' and I have experienced such cold while skiing a cpl years ago so I know what it means to be 'under geared' in the outdoors. My whole group was a bit under prepared for how cold it was but obviously it was good that we were just at a resort and not out in the back woods. If we had I certainly would have packed warm clothes but I digress.
This is still slightly moot in the sense that I have already concluded that I will be getting one from each category to use in varying temperatures as needed (not necessarily together). A cap3/4 and a puffy (like a Montbell Alpine? which has been suggested a few times I think).
I posted it a bit earlier and am only just getting used to the forum profile here but I am in Colorado. I do intend to try it in my backyard so to speak it just wont get truly cold enough to test this week but I will still try to be sure.