I am proposing that it is using the SD computed as I describe above. This is not an SD derived from historical data.
snip stuff with which I do not necessarily agree.
You suggested some evidence exists for this to be the case for long bonds. Please try to be complete and fair. Also, do not assume this means I insist anything about shorter maturity bonds. Too often IMO you're trying to force me into defending a view that I never embraced fully. This is an exploration. Also, only in the last half-day or so have you offered to produce any citations of your own. To do a full analysis would ultimately, in my experience, test the moderators' patience, meaning there is no assurance that submissions will be posted. Though any resentment on their part in such instances is generally understandable. All things considered, I do not have incentive to continue.