I myself use it like this: 860 -600 = 260.
two level above that is 2000. Then, I add the excess exp for that to my level to 2260.
Remembering @ohko's word about the person who has 70ish level to level 5 though, he said that it is up to us if we want to level to 6/7 (in term of exp).
so, if you...