Those 10 lvs different means she can be 10% stronger in stats. Plus given her class, I would say her INT/WIS/MAG is +3 or +5 per level so her firepower has to be 30% to 50% stronger. Also depend on how high the hero party's MAG RES/MAG DEF growth.
If it is not (100+lv)/100 rpg attribute type but...