I Guess 300% of us Current exp and i hope it to mutch beter then 3 lvls i wil explane you xD
make youre char 99.99% before you get the event Why? .....
then you wil get '!! 4lvls up !!'
99.99% X 3 = 299.97% + youre current EXP ''99.99%'' make 3 lvls and 99.96% exp (4lvls up) !!!! vrry mutch beter i guess

If you dont do that For Explane:
50% X 3 = 150% + your current EXP 2lvls up
and stupitst thing you can made

dont do this >< :for Explane
2% X 3 = 6% it make me and you sick
but so its youre shoose xD what you want
cheers,