Yes, there is a 'not equal to' option in 'system > condition > Compare two values'. But that is not what you need.
System > Every Tick
Sub EventS ... Local variable 'Exceed' = 0
........................System > Compare two values ... First = Player.xpplayer ... Comparisation = '> is greater then' ... second = xptotal
....................................ActionS: Set 'Exceed' to xptotal - Player.xpplayer
.................................................Set xptotal to zero
.................................................Set Player.xpplayer to 'Exceed'
.................................................Level up