Runaan bolt damage lost on Ashe's Ranger's Focus?

i just did a test in custom game with ashe with no runes, no mastery, only getting 1 runaan , 4 Cloak of Agility i got 100AD, 60% crit chance

then activating the 5-stacks-Q with only 3 caster minions in sight i got two damage indicators(**23 **& 93) on both secondary target, resulting a 116 damage on each secondary target however using the formula (bolt damage)*(passive)*(Q)+(runaan on-hit): 50*1.7*1.35+10=124.75 there is some damage lost(8.75) but i can't figure out which portion is wrong nor which portion contribute to the damage indicators

now i wonder how exactly runaan bolt interact with ashe passive&Q and also the corresponding calculation, is it the damage indicator not accurate enough or is it probably a bug?