10 hours at 2.5 doesn't sound too bad... That's what I would expect with my princess this time of year. Your temps seem a little off, but that may be because you are starting very low. I never let my house drop below 68 because it is hard to get back up. (Propane)
Also, I see the temperature swing too. I turn up the thermostat when the wood is mostly coals.
I figure if the low is going to be 12 degrees f, I can get a 12 hour burn at 2.25.
If the low is going to be 24 degrees f, I can get a 20-24 hour burn at 1.5. Although I do struggle with stalling due to marginal draft.
2200 sq ft, medium insulation, keeping house at 72. Wood has a huge impact on performance. Pine/ popple = shorter burn times. Birch/ Tamarac = longer burn times
Webby3650,
Do you have an active flame at 2.25?
Hang on now, are we assuming that the stat settings on the ashford are the same as other BK stoves? On my princess, the #2 setting is exactly in the middle of the normal range which is 50% "throttle".