I believe they are two different things. One, in the Present tense saying "I don't believe in DID" is discounting someone else.
While talking about having difficulty with an alter who doesn't understand about a DID system is the issue that freewill brough up and asked if anyone has experience with.
I have experience with that, and it is that which i was sharing with free... and now with perna who is asking good questions that the system is having a hard time answering.