I just spoke to an agent who insisted my Tier 4-5 certificate converts to a Category 1-4. I asked her to speak with someone else and double check since it doesn't make sense... She insisted and I said go ahead and do it (I wanted to cash out for 315k as another agent offered last week)

And she did. I got a Cat 1-4 for a Ritz 4-5 cert, the worst conversion in history. I'm too busy to HUCA right now but I've sent Bonvoy a message on Messenger, let's see how many weeks a reply takes.