Marvel Comics Mr Hyde

It's Captain Marvel (DC) Billy Batson and the same person or different identities?

In modern comics, "Captain Marvel" Billy Batson in an adult body (such as Batman put the Batsuit), or Captain Marvel and Billy Batson different people (like Doctor Jekyll and Mr. Hyde)?

They always been portrayed as the same person (only Captain Marvel is older and has the wisdom of Solomon). But if you read Shazam The Monster Society of Evil, Jeff Smith writes that they are separate identities. For most modern comics, Captain Marvel and Billy Batson are the same person. Now that Marvel is Billy Batson, Freddie Freeman is the new Captain Marvel (or Shazam) and its obvious they are the same person.

Marvel Comics: Mr. Hyde