No, it hasn't changed. For some people it's 10; for others it's 25.So now it's changed back to 25 posts for PMs?
Last time I said 25, you said it was after 10.
The difference is when people started their account. IIRC, the case you're referencing was one where it was a very old account that had never been used to post. If an account is old enough, it gets PMs after 10 posts. New accounts get them after 25. New supporting accounts get them...uh...I dunno when.
ETA - And all this is subject to change anytime there's a software update or a higher level admin gets a bright idea.