Re: sr.member,hero, legendary show an example in earnings of these merits
The fact that you were able to get merits for your posts means the system works.
I was a member already when introduced merit 
and I can't say how it influenced the achievement of new merit. I would create a new account for the experiment but I'm just learning what the crypto world is and it will last longerhttps://bitcointalk.org/index.php?action=merit;u=1350339
All your merits are awarded.