I’m entering a billing code, but the MFD tells me it’s invalid.
Occasionally departments make changes to billing codes and structures. This information will come out to staff via email, in advance of the change. It means that at some point a billing code or codes may be deactivated, and reported as invalid if an attempt is made to use them. If you can find no record of any communication from your finance team regarding a change to a billing code, please log a call for investigation.