If I bought a $20 variant of ChatGPT that gives me a,b,c,d versions of ChatGPT those versions should be able to read conversations of each other, BUT the difference is that they are within MY account. So another person’s $20 account that has a,b,c,d cannot be read.
This would hold back me having to reach ChatGPT everything across all versions every time I use a different version and then ask it something about a past conversation I know I had with it, but forgot which version I had the conversation with.