Create tax determining factor setusage tax box allocation with determining factor purchasingcategory

Summary:

I'm working on configuring Tax Box Allocation Rules in Oracle Fusion and wanted to use Purchasing Category as a determining factor. However, while creating a Tax Determining Factor Set with Set Usage = Tax Box Allocation Rule, I noticed that Purchasing Category is not available in the dropdown list of determining factor names. I’ve verified that other factors like Product Fiscal Classification, Transaction Business Category, and Place of Supply are supported — but Purchasing Category seems to be excluded.

Questions

1. Has anyone successfully used Purchasing Category in Tax Box Allocation Rules?
2. Is this a known limitation in Oracle Fusion?
3. Are there any recommended workarounds (e.g., mapping categories to Product Fiscal Classifications)?