Tbh, your answer is just plain wrong... Why do I think it is wrong:
1) The higher the skill, the higher the chance of hitting, we all know that, but I'm pretty sure the chance is NEVER 100%.
2) I have a paladin with 123 distance fighting skill and it still misses sometimes (even with a bow giving me extra %)
3) The creature physical defense has absolutely nothing to do with the chance of the arrow missing or hitting, the defense will be applied over the damage the creature would take, it doesn't prevent the creature from being hit. If that was true, no paladins would ever hit an arrow in a Ghost, but they do, don't they?