Skill checks for Magic Item Creation

Question

Let us say I want to create a Ring of Sustenance. The DC is 5 + CL (in this case 5). Since I am a Wizard and do not know the spell 'Create food and water' and want to do it in half the time I put +10 on top. So the DC is 20.

The rules for item creation say

At the end of this process, the spellcaster must make a single skill check (usually Spellcraft, but sometimes another skill) to finish the item. If an item type has multiple possible skills, you choose which skill to make the check with.

Looking at the Creating Ring part I find

Skill Used in Creation: Spellcraft or Craft (jewelry).

and finally there is another rule that has to be applied

Item Requires Skill to Use: Some items require a specific skill to get them to function. This factor should reduce the cost about 10%.

After spending money and time I choose Spellcraft (since I do not have Craft(jewelry)) and roll a 22.

I have created the ring but does the last rule for getting a 10% discount also apply or do I have to do another skill check? If so, when do I have to make the skill check and can that be a Spellcraft check as well?

Answer 1

That last rule is only for magic items that requires a particular skill to be able to use it, and as such has nothing to do with the skills needed, or used, to create them.

Say you crate a "Ring of the Thief", which requires 5 ranks in Stealth in order to be operational. Then, and only then, would the cost of creating this ring be decreased by 10%. A Ring of Sustenance that can be used by anyone does not fall into this category.

Answer 2

The 10 % discount applies when creating and designing a new magic item that requires ranks in a particular skill or ability to use.

Many factors must be considered when determining the price of new magic items.

That is, if you were to create a Ring of sustenance that only sustains (say) jewelers, then it would be cheaper.