Base price of 30 ... *2 for being worked into gunpowder, then there is no bonus for double working something.
Silly me. I got confused. You are right, I see it now.
It does more than add clicks,it adds trips to the mine and back which adds more time.
No it does not. After wipe ammo was supposed to cost more. The current price of 100x 10mm ammo should be 2 metal parts and 12 gunpowder. By making it 50 for half of the price you can make 50, 150, 100, 200, 250, how many you like and then have more cooldown left to craft other items. Otherwise you might end up crafting 100 ammo and not having enough crafting timeout left to make a 10mm gun and are stuck waiting. It gives players more flexibility.
Is it at all possible to seperate cost and time?
No. In a game where everything is free and only takes time, cost has to be based on time spent getting it. Because it costs you nothing but time.
Im not 100% on the price of 50 rounds right now but I believe its something like 450 caps and I would have absolutely no problem with getting that same ammount for 100 if it means I have more time away from mines and benches.
If the price gets lowered then it will be less expensive & faster to make said ammo and that will cause people to use it over any other ammo. The devs' aim it so make each level of crafting take about the same time to do for any item so that no item from level 2, for example, has an advantage of being faster to make than the other ones from level 2.