You quote it, and still don't read it.Swift Quiver
You transmute your quiver so it produces an endless supply of nonmagical ammunition, which seems to leap into your hand when you reach for it. On each of your turns until the spell ends, you can use a bonus action to make two attacks with a weapon that uses ammunition from the quiver. Each time you make such a ranged attack, your quiver magically replaces the piece of ammunition you used with a similar piece of nonmagical ammunition. Any pieces o f ammunition created by this spell disintegrate when the spell ends. If the quiver leaves your possession, the spell ends.
Focused Fire = unlimited ammunition for 4 shots per round in one enemy
Volley = unlimited ammunition for any number enemies in 10 feet radius + 2 shots bonus per round
"Each time you make such a ranged attack"
"such"...? Such as what...??? Such as the attacks described in the preceding sentence.
"you can use a bonus action to make two attacks"
Specifically the 2 attacks made as a bonus action. The spell does not say it replaces ammo from *any* ranged attack, nor from *all* ranged attacks...but from *such* ranged attacks.
So yes, it will replace any and all arrows used for those bonus attacks..... not for your regular attacks, and not for your Volley attacks.