The agents have no clue. Better agents would tell you they do not know what would happen after program merger. New or incompetent agents that unfortunately Marriott seems to have many of them lately, dont have a clue. They just tell you what the existing rules are. But YOU should know better that the existing rules go out of the window come August 1st!
For the most obvious - the categories of today, DONT correspond to the categories after August 1st. Just by that token, you know what you have now can not attach to the category of the same "number" after Aug 1st...

I have posed a link for the thread in Marriott Insider, the poster detailed out the "Non Answers" from a staffer from "Mr. Marriott's Office". It is worth your time to read it so you know the agent who told you whatever, actually has no knowledge on what is going to happen. Either the agent just lied to you to get you off the call, or the agent genuinely did not have a clue. I would be more generous to say s/he had no clue.