Question about PM.

When I first joined here, I read all the rules and FAQs carefully. I'm sure I read "You need to have 15 posts to be able to send PM" or something similar. I only have ten posts now. But when I tried to PM someone, it got through.

My questions are: Is this a bug? Or are posts in Lounge and Introductions considered for PM? Can I PM without getting an infraction or ban?