Bow damage formula?

[Goregasmic]

Do we know the formula? After some googling I haven't found anything conclusive.

I remember reading somewhere the damage bonus followed that formula:

45+dly weaps = base + (delay - 31)/3
where base = ((level-7)/3)

but then I can't find the source anymore.

I also read a torven post saying it is basically: bow damage + arrow damage + mh damage bonus so basically it would be the good old ((Offense+STR)/100) formula applied to bows then split into a d20? Right now i have a 12dmg bow with 5dmg arrows and 23 damage bonus which yields 50 but I'll hit anywhere between 27 and 64 or so (non crit, no double damage) often in the low 30s range.

And yeah before anyone says it I know bow damage isn't very significant but it is hard to tell which bow is better/worse if you don't even know on which basis the damage is calculated.

Thanks.