Is it okay to add a field to the Project flexfield PA_PROJECTS_ALL_DFV?

Hello.  We are on EBS 12.2.6 and have a need to add a new custom field to the project setup screen.  I found the descriptive flex field PA_PROJECTS_ALL_DFV (Application=Projects and Title=Projects) where I can unfreeze it and add my new field, but I don't normally deal with the Projects/Grants module and am unsure if this is acceptable to change.

Is there any reason why we should not customize this flexfield with a new value?  Would any future patching overwrite the custom field?

Thanks for your input.

Lydia