Message Count: (as listed in your member card) - should be analogous to "Posts" in other forum software. "Message Count" should definitely be called "Post Count". Message is definitely a confusing word for this context.
To illustrate that message count on the member card is a misnomer ... if you click on someone's profile, ie. mine, it says "Postings", not Messages. Time to tidy up the language here.
Messages, is easily confused with "Private Messages", and this is not what xenforo is trying to convey here.
Your question is a little hard to understand, if you rephrase it, I can get into more specifics ... "After massive imports across different forums" - does this mean you imported for forum into xenforo and the member's post count didn't show up in xenforo ?