Dunno about miles, but I tested 2 levels on my bbs02. 5 wh/km on the lowest level (max 150w), and 7 wh/km on level 2 (max 300w). This was on a semi-hilled route with 3 km climb in it.
I also see if I use the throttle, it really drains the battery, so it should be avoided for touring. My dream...