Historically the Doyle rule was used to determine actual expected board feet. Now mills are much more modern and usually average 20-30% over doyle depending on log size. That doesn't mean you are getting screwed. It is best to view all log rules as a means of the buyer determining value, not of actual usable board feet. There are many log rules, scribner, International (both 1/4 and 1/8 inch), cubic feet, cubic meters, ect. The doyle rule is the traditional measure in the east.