You can only get max 14 activity every 2 weeks and they CANNOT be stacked toghether: when you have an old account that is 1 year old and its on newbie rank. Then you start posting 40 posts - its the same, the acitivity will only rise 14 points. No matter how old it is. The account will only get 14 activity every 2 weeks.
If you have more posts than activity, then you can just post 1 post to get up to 14 acitity. But that will only increase the activity by 14 MAXIMUM. If you forgot to do so in 2 weeks, than you cannot stack them toghether and make 28 posts to get 28 activity, you will only get 14
So the advertisment is misleading, the title should show: Selling Newbie Account [0.06BTC]
Which is ridiculously expensive...
Well, good luck than!
i wonder how did you become a Sr Member without knowing how the activity is growing in some way. did you miss the fact that he has posted atleast once in that every 2 week period so he can still get Newbie to Full Member but reaching a certain number of post?