Hello @AnthonyN, welcome to the QuickSight community!
Normally when you receive this error message:
Table calculation attribute reference(s) are missing in field wells
It means that the visual requires one or multiple of the fields you are referencing in the calculated field to run. The nice thing about tables is that you can add the fields that are being referenced, figure out which ones are required, then choose to hide them from the table so they are not available in the display. This will be the best way to handle this scenario.
I will mark this response as the solution, but please let me know if you have any remaining questions and I can guide you further.