I will have to slightly disagree The only better thing in a new account is the absense of smart pricing which eventualy vanishes in some time
Is there such thing as smart pricing?? New publisher gets better rate only because the new publisher tend to have lower traffic than existing publisher.. It really depends on the niche, but logically, if you get more traffic, the rate per click goes down, because your traffic eats up the advertiser's budget.
I don't think that's a fact unless any proofs can be indicated. It all depends on your ecpms and ctr, if your ratio for unique views: total views is significantly low, chances are you'll receive a high amount per click as oppose to ratios that are significantly apart. That's why I always make sure that I am optimizing my ads and not including like 3 ads at one page, because the more and more you placed, the lower the ecpms go and if you get more clicks and less ecpm, chances are that if you put 1 ad and get less clicks can be somehow the same or similar. At least this is my experience from adsense.