I was wondering about situations as well where "No Score" or the like is returned. I agree that the 9/13/17 preamble seems to imply to use "Not Applicable," but as is often the case with the CFPB clarifications, they just refer to the previous issuance that still leaves doubt on what the correct method would be based on the scenario. It seems to be clear that 8888 is used when a credit score was not relied on in making the credit decision. There may be cases where the "No Score" response is the reason for the denial, or was at least a factor in the denial decision. In those cases, it would seem that 7777 would be an appropriate code to report. I guess they tried to clarify with the 2019 FIG:
c. Use Code 7777 if your institution relied on a credit score that is not a number (e.g., a credit score of “Meets Thresholdâ€). Code 7777 should not be used if a credit scoring model that produces numeric credit scores returns a result stating that the credit score could not be determined.
However, I still think "credit score could not be determined" does not necessarily correspond with "No Score." Also, the fallback option to Code 8888 doesn't seem to match precisely, due to what was stated above.