I noticed a couple things about BoD's.
1) resets don't seem to work. That is having a low level character get low level BoD's, then completing them on your higher level character to reset the clock to get another BoD. Does turning in a BoD not reset the timer here?
2) When requesting BoD's I sometimes get the message "You can get an order now. Please try again". A good example is when I go to the tailor near brit bank. I get a BoD from the tailor, and try again right after getting the message. If I then ask for a BoD from the weaver he gives me one, then both say I have to wait. Blacksmiths seem to do the same except I cannot find a second to give me one. Today the fletcher wouldn't even give me one.