Issue adding new formula to Cross-Tab

I'm not too bad creating formulas but I've never had the need to add them to a Cross-Tab report. I can see the new formulas in the Report Fields section when in the Formula Editor and Field Explorer, but not in the Report Fields section when creating or updating a Cross-Tab.

I've done everything I can think of. I'm guessing that it's because of some issue with CR 8.5, but I don't have a choice right now. I can't upgrade due to compatibility issues.

Any ideas?