Many Western Mountaineering sleeping bags, including UltraLite, have continuous baffles. They say that this allows user to shift the down to the top of the bag for cold nights or shift it to the bottom for warm nights. See http://www.westernmountaineering.com/index.cfm?section=about&page=Product-Details#continuous
I sleep on my side and I frequently turn from one side to other side at night. As I turn, I turn the bag with me somewhat, especially close to my head (the bag hood) and upper torso. I am worried that on cold nights down will unintentionally migrate from the top to site/bottom, leaving not much down on top and compromising insulation there.
How bad is the unintended down migration in practice when turning frequently?

