I am very interested in this discussion but I am having some conceptual issues with the decission to retreat the Longbow once they are out of ammo.

Thiis is not because it is a sensible thing to do (it is) but how can you define this as a victory for the Longbowmen? Even if they have scored more kills up to this point they are the ones who quit the field while the crossbows are still firing? In an SP battle some unit (if not the Longbows) are going to absorb those bolts.

I guess if the effect you are looking for is the decimate the enemy missile troops and then start advancing your infantry to engage once your missle units are spent then Longbow has superiority going by your statistic. But is a defensive engagement where you are defending with Longbows then unless they are capable of actually driving off the enemy xbows before they run out of ammo then those xBow bolts will hit some of your units.

So I would say the Longbows superiority is situational. But then I guess that fits with the whole, there is no uber unit thing. Just the right tools for the right job, decent tactics and use of ground and a little luck.