cant really follow you there. what you mean with secondary projectiles as in another accountance of these arrows aside from the 1 damage they do?
If you look, for example, at the calculation on screen at 2:40 in the video, itâs conflating attack and damage. 9 x 3 attack every 3 seconds doesnât cause the same damage as 3 x 6 attack every 2 seconds when there is armour. He uses the term DPS throughout the video, but the calculations all relate to APS rather than DPS. This is a problem for single projectile units, but itâs a particularly pronounced problem for units with secondary projectiles where the secondaries have low attack.
E.g. the video says Elite Chu Ko Nu have 14 + 4 x 3 attack, a total of 26 attack. Against 2 armour, this will cause 12 + 4 x 1 = 16 damage. For simplicity, consider a castle with 13 attack (11 damage against 2 armour), and pretend there is no difference in firing rate. To preserve attack, the game would add 2 arrows (26 attack) if you garrison 1 Elite Chu Ko Nu. Against 2 armour, 3 arrows with 13 attack each would cause 33 damage, vs 27 damage for the unit and castle separately, i.e. the unit has added 22 damage rather than the 16 damage it would cause on its own. This is what SotL talks about at 5:50 in the video.
Basically, when attack is equalized, damage is higher when that attack is achieved by having fewer projectiles with higher attack per projectile, due to how armour works. To more closely replicate the relationship between attack and damage for a unit with secondary projectiles, the castle itself would need to also have secondary projectiles. I think a small amount of extra damage to reflect the arrows being fired from higher up is okay, but 22 vs 16 seems excessive.