Awesome, really helped m8. I did experimented with 1 point after writing my post. And it worked same way you said it.
Now I dislike that Blightown with a passion! Poison poison covered in poison with small dickheads spitting poison arrows from somewhere very dark! I am already at 9k souls and keep doing on that part. This last run I cleared everything and had only 1 pot left, so I just went back in to reset. Those bastords do give 500 souls, but it is annoying to kill them!
Any poison resist pots in game which I can swallow before fights to get my poison resist higher?