MW adds onto your +bonuses. So the boost shows under there.
For example let's say in the stats window, I have 730 (700+30) int (I wish), the +30 being from equips and such.
If I cast my MW (which is lv19, so it gives 10%), then in my stats window it will show 800 (700+100), because 10% of 700 is 70 and 70+30 = 100.