there is no difference option there. ill explain better.
the user collects xp and is stored in xp "xpplayer" variable
is then added to "xptotal" total variable
if the user "xpplayer" variable exceeds the "xptotal" variable then
the player levels up and the "xptotal" variable is reset to 0 and whatever is left from
the xpplayer" variable get added to "xptotal" so they can get xp to level up again
hope this helps