Hi, The screenshot character learnt 30 level of Arrow Bomb which will be dealing 130% of damage but it is dealing 188 damage.
Arrow bomb has a weird and some what complicated damage formula refer to here: https://www.google.com.sg/amp/s/ayu...009/09/06/maplestory-formula-compilation/amp/ From what I understand the first target you hit actually only takes 50% damage while the splash damage gets your skill multiplier (i.e. 130 /150%). So 50% x 390 (being the lower end of your range) - weapon defence calculations. 188 is a very possible number.