winged and griffon-feathered prefixes are applied twice
It seems that both of these prefixes are applied twice in the range calculation. Most likelt first time before adding range boost given by missile weapon skill and another time after adding it.
For example normal arrow + long bow of accuracy with grandmastery in bows (+5 in range) had base range of 19 (so 14 without grandmastery bonus). With same bow but winged arrows base range was increased to 141 (scroll of great identify states range is tripled). And 141 = ((14 * 3) + 5) * 3.
With freshly rolled archer (and no range bonus from missile weapon skill) the base range was multiplied by 9 (from 3 to 27).
With griffon-feathered arrow base range was increased from 19 to 27 (scroll of great identify states that griffon-feathered increases range by 4). Again 27 = ((14 + 4) + 5) + 4.