@shushila: Nice information. You have done excellent work by presenting the calculation about the earning by upgradings on this forum. I think that you can show this to the admin through pm to him and he also will be convinced that he should increase the incentive for upgraded members. Then only the members would be interested in upgrading on this forum.
If an upgraded member misses even two days posting then his earning will reduce by $1.6 and so he would earn $17.4 (after deducting the cost paid for upgrading). In this case the earning of an upgraded member will be less than that of a standard member (Ofcourse working for the whole month without missing a single day). I think that the admin has not given enough consideration to upgrading system as the forum is quite new.