So who knows, it really depends on who you get when you call. My third comped cruise via mailer I used a spare certificate I had and the obc didn't show up on my invoice that was emailed and I had to call back and get it added, they were like oops I'm sorry, our bad 14991 likes 177 talking about this 600 were here. My second instant cruise certificate I was extra careful when talking to casino royale and learned that the obc is on the emailed invoice they send you so I double and triple checked and I got the obc as promised Club Royal Caribbean Casino & Members Club, Port of Spain, Trinidad and Tobago.
Since it was only 50.00 obc and I was new to the program I let it go They kept on saying onboard that the wording of the cruise next booking was 'dollars off' my cruise and since it was comped, I get zero. My first instant cruise certificate booked with the cruise next deal= didn't get obc even though the booking lady said I for sure had it and I couldn't get it resolved onboard. I've heard different stories on this and have a limited personal experience as I've only been prime since Sept and haven't done the prime tier cruise yet but here it is