There is difference in giving rate already...
Look at the rankings on TB and SL. 1st place on TB has rate around 27, but on SL it's only 21.
Caused by 2 things:
1) Many people have reserved their names on SL so they won't get ranked there, SL list is dropping, TB is rising.
2) On TB the PPM limit introduced by SL in 2007 is not applied. If you get 30 ppm this will count as 30 ppm and not as av ppm*2.25