We closed a loan in February but needed to collect an appraisal recertification/completion fee for the appraiser to go out again in spring/summer to verify the outside work (such as landscaping) had been completed. We received the appraiser bill recently and it is $50 lower than we had charged the borrower. We know we must refund the customer but since we are well past 30 days post closing do we do a post consummation CD or skip it since we missed the 30 day timeframe?

You should be fine as long as you disclosed in good faith initially and refund the difference within a reasonable amount of time after discovering that the borrower overpaid. I do not believe that Regulation Z contemplates a situation in which a discrepancy cannot be identified until greater than 30 or 60 days after loan closing. Document the file as to the date the appraisal invoice was received.

As long as you're already providing a refund, I would also issue a revised CD with the actual appraisal completion fee, although you have an argument that this is not strictly required. This is just the best customer experience in my opinion.