Would you allow "modified" paper cartridge? At what price?

With the gunsmithing feat, a character can craft bullets, pellets and black powder for 1/10 of the market price, and alchemical cartridges for 1/2 the market price.

This means a regular shot will cost 1.1 gold, and a paper cartridge 6 gold per shot, while the market price is 11 gold for a regular shot and 12 gold for a paper cartridge (the 1 gp diffence being in the paper and the was used).

Now, clearly this price disparity is there for balance reasons. A character with the gunsmith feat can shoot cheaply, OR quickly.

But "special" bullets can also be crafted, like silver or adamantine bullets, at the cost of 7.1 gold per shot for adamantine bullets and 3.5 gold per shot for silver bullets (powder charge included).

That said, would you allow players to craft paper cartridges with special bullets (silver or adamantine), and if so, at what cost? IE. how would you break it up? Because the difference is pretty huge.

Real world logic would tell me to go with option 1, the cheapest. However, game logic and deconstruction of the regular alchemical cartridge seems to indicate the second, and much more expensive, formula should be used. Your opinions?

I think option 2 makes more sense, Option 1 has some flaws in the math

1: You use the material cost for the bullet, but subtract the market cost from the paper cartridge, then divide everything by 2, when only the paper cartridge would be 50% off.

Think issue is the bullet and powder is 10% of cost, but the cartridge part is 50% off, so its hard to adjust the material costs to craft a custom Cartridge.

market Cost of Paper cartridge:

Bullet 1g
powder 10g
alchemical paper/stuff to hold it together, 1g

total 12 g

makes sense right?

if you use the material costs, it gets wonky:

Bullet 10s
Powder 1g
Alchemical paper/stuff to hold it together, 50s

total 1.6g

See what I mean?

I would just make the bullets cost nearly the same as arrows. Why? Because gunslingers do on average less damage then archers and they shouldn't be punished more then they already are.

The best I can come up with it that there is 44 sp worth of materials that go into making the cartrages

Regular cost: bullet + powder + cartrages = cost
1+10+1=15

Crafting
.1+1+.5=1.6

But we know that cost is 6 gp so 6-1.6=4.4

So, admantine paper cartrages would be

6.1+1+.5+4.4=12 to craft on the cheap

But that would mean that it would cost only 24 gp to buy...

I'm guessing most people will say it would cost 36 go to craft ((61+10+1)/2) but that would mean that our random 4.4 just shot up to a 28.4, but who really knows.