I am not asking you to change the rates. And as you said, it is Arlianin's (lol dont know how his name is spelled) server and not Radonia anymore.
About the old rates.. I dont remember the exact numbers, but I am atleast sure that it was quite high from lvl 1 to lvl 8. And then lowering once in a while until lvl 20 when it became 4x exp all the way to infinity!
1-8=10x~
9-20=7x~
Then it was 4x as you said ^^