Looking back at when
I measured modal values for Huntsman and Rain Caller, I found the modal value to be bow damage + arrow damage + 1 + damage bonus. At the time I was focused on bow damage + arrow damage + damage bonus and dismissed the off-by-one, saying it "does predict the modal value pretty well."
I think that about wraps it up. Archery by anyone will have a modal damage of bow damage + arrow damage + 1 + damage bonus, with the average damage being higher or lower than the modal damage depending on what mob you're fighting. If you're specifically a ranger above 50 shooting at a stationary unrooted mob, modal damage is 2 * (bow damage + arrow damage + 1) + damage bonus. If you're using the BFG in primary, the damage bonus will be the 2h damage bonus.
So to compare bows purely for bow-rotting rooted targets, you want to look at (bow damage + arrow damage + 1 + damage bonus) / delay. If you're gonna be shooting at targets someone else is fighting and you're a 50+ ranger, look at (2 * (bow damage + arrow damage + 1) + damage bonus) / delay.
And always take into account Snaggle's point about arrow efficiency and Botten's point about fast bows being in danger of overcapping on haste.
Case closed.