Alchemical archery cost for things besides arrows

[thistledown]

The alchemical archery section of the alchemy manual says that you can use it with other ammunition (not firearm ammo) and piercing thrown weapons. How do you calculate the cost for these? I'm specifically looking at Raining and Phermone applied to crossbow bolts instead of arrows, but the question applies to the whole section.

[Blub Blub]

Since the costs listed are "per arrow", and crossbow bolts are specifically allowed, why wouldn't you just price it "per bolt"?

I just did this with my Bolt Ace in PFS, and didn't see any other way of doing it.

(I.E Durable Arrow 1gp, Adamantine Durable Arrow 61gp, so Durable Crossbow Bolt 1gp, Adamantine Durable Crossbow Bolt 61gp)

[thistledown]

Since the base cost for arrows and bolts is different (20/gp vs 10/ gp) I thought I might need to apply the same difference. So a durable bolt would be 1.05 or something.

[Helcack]

That's what I do thistledown, but it isn't stated exactly how to do it anywhere. Durable masterwork viridium shuriken are my favourite.