This is an easy fix, I can check your underlying code get the field to work in under an hour.
I'd been working with a Salesforce ISV building advanced reporting for banking institutions. Presently I work with Non-Profits donning hats as a Developer, Administrator, Product Architect and Trainer.
Let me know when we can start off. I'd just need the credentials of the Sandbox and the Production org and can have your deployment validated under an hour.
Best,
Allen