I agree that it does go further to say about refunding the buyer in full - but also clarifies that it relates to a return or cancellation request.

If I have inadvertently misled sellers here, I apologize.  My intention with the post was to be of assistance.

For my part, I have it in writing that FVF adjustment is applicable for partial refund of postage.  So if I need to request a FVF credit in the future, I will refer whomever to the transcript.