Give me some time, let me answer this later. You will get your answer why changing the quivers is fair. Just give me some time, I will edit this post. Must work now.
A. Range between the archer and the enemy a. Archer is using Bodkin Arrows
P1. Archer is effective against polearm infantry (no shield), same for the Bodkins
P2. Archer is effective against twohand infantry (no shield), same for the Bodkins
P3. Archer is effective against light cavalry (shooting the horse), the Bodkins are not
P4. Archer is effective against other archers, the Bodkins are not (due to light armor and low ammo)
N1. Archer is neither effective nor ineffectiv against throwers (because it depends on shield/no shield), the Bodkins are neutral (depends on the armor)
C1. Archer is ineffective against heavy cavalry (high armor and speed, I tested it with Simon on a duel server), the Bodkins are not
C2. Archer is ineffective against crossbowman (the crossbow is much more accurate and it's rather a far range missile weapon while the bow is a medium range distance weapon; throwing weapons are low range distance weapons), the Bodkins are neutral (depends on the armor)
C3. Archer is ineffective against shielders, same for Bodkins (due to low ammo, you really do not want to waste them on a shield wall)
b. Archer is using Tatar Arrows
P1. Archer is effective against polearm infantry, not the Tatars
P2. Archer is effective against twohand infantry, not the Tatars
P3. Archer is effective against light cavalry, same for the Tatars
P4. Archer is effective against other archers, same for the Tatars
N1. Archer is neither effective nor ineffectiv against throwers, the Tatars are neutral (depends on the armor)
C1. Archer is ineffective against heavy cavalry, same for the Tatars
C2. Archer is ineffective against crossbowman, the Tatars are neutral (depends on the armor)
C3. Archer is ineffective against shielders, not the Tatars
B. Low distance between the archer and the enemy/ Crossbow not reloaded in an open field P1. Archer is effective against infantry with low athletics
P2. Archer is effective against crossbowmen
N2. Archer is neither effective nor ineffective against throwers
C1. Archer is ineffective against light cavalry
C2. Archer is ineffective against heavy cavalry
C3. Archer is ineffective against fast infantry
This should be complete (despite the HA, excuse that). At the moment, most archers use 2 stacks of Bodkins due to the piece damage. I come to the conclusion that allowing them to switch to tatars by pressing 'x' etc. would make them more effective against light cavalry over far distances (ride some fast zigzag) and against other archers in general. This means, allowing them to change the stacks of arrows they are currently using encourages them to fight each other and rather spares the infantry from archer fire.