Further to this, what penalty is applied when your throwing proficiency is too low like this? Does it actively reduce your accuracy and/or damage?
My character Boreal always used to lug around a few javelins or war darts to hurl before closing in melee, where the majority of his proficiency points were invested. I would have about 50 in throwing just so there was a reasonable chance of hitting the target and dealing a bit of respectable damage, but didn't want to specialize in throwing because it would reduce how much I could put into the melee skills.
If there's a considerable penalty from low throwing skill, then I'll avoid this sort of tactic after my next retirement, so any specifics on it would be greatly appreciated.
-John