I've got some updates on the subject.. yesterday I chatted to the admin directly through skype and asked him a couple of questions.. and finallly got some answers. Not all the answers I was seeking for but some answers at least.
Question 1: How do the ads system work?
Answer: He said it shows hidden ads under a background and they might come up as a pop up sometimes.
Comment : Well since I've used it I've never seen a single popup.. but chrome blocks my popups anyway..
Question 2: Why aren't all my visits credited even if they are in the 3 tiers?
Answer: The system counts all of them and we can see our history in the account page. However it only credits unique visitors for all members.. This means that if some other member has brought a visitor first he will get credited. If I bring the same visitor (IP) on my site afterwards then I will not get credited for that visit.
Comment: That explains why I get credited only 1/5 of the actual visitors I see in my graphs.
Question 3: Why are autosurfs allowed and traffic exchanges not..
Answer: He told me that they currently accept traffic exchanges.
Comment: So it is ok to use EasyHits4U as well. I suggested that he makes that visible somewhere in the site and thanked him.
Edited: Removed content.. as I actually got his reply.