I doubt they "switched" to a credit; 'continental' breakfast has been available for Diamonds for free, full buffet for a $10 upcharge ($10 x 2 + tax/gratuity = $26.xx the previous posted mentioned). So (making up numbers here) if the continental breakfast is $34 and the full buffet is $44, then you could call it a "breakfast credit" of $34. It's all the same thing.