Jurisdiction entry - Precedence Level field values question

Hi  - I have a question about the "Precedence level" field on Jurisdictions page.

We are a typical US based AR Sales tax setup with State, County, City geographical and tax hierarchy.   Our users get an error message whenever they are adding a new CITY level jurisdiction manually.

The issue is with the field called "Precedence Level" - the message states "This precedence level is already in use. You must create unique precedence levels for tax jurisdictions that apply to the same tax.   In this case - the tax is called "CITY", its the city tax portion of the standard 3 tiered Sales tax set up.   So if we are forced to always choose a precedence number that is different from the "300" value that is already on all of our upgraded records (11i to R12.1) , then we will run out of numbers at some point.   The only