Alright, the rules state that if you gain allomantic power from a spike you can never increase that power.
My question is, what happens if you have both natural and hemalurgic powers with the same metal? Can you enhance up to a total rating of 10? up to 10+the spike's rating? what?
To make this clearer:
Coinshot Sasha Mance (A: 5) is captured by the Steell Ministry. She escapes, but has a memento in the form of a spike granting her Steel 4. So her total Steel rating is now 9.
Case A: She can spend 6 Advancements to enhance her natural Allomancy to 6, granting her a total of 10.
Case B: She can, over the course of several sessions, spend 30 Advancements to enhance her natural allomancy to 10, granting her a total Steel rating of 14.