What does outgoing and ingoing health items do? Does it work in battle?
They boost the health applied by the healing spell. If you have an item that boosts outgoing, and you heal another for say 420, a +4% would do: 420 x 1.04 = 437
If someone healed you, and you had a +5% incoming booster, you would heal: 420 x 1.05 = 441
And if you had both and healed yourself: 420 x 1.04 x 1.05 = 459
