Anecdotal at best, most rogues didn't even use poison and I sure as hell didn't play one on live. I just can't imagine being "
master" at apply poison and failing so often.
This is quoted from the p99 wiki poison guide:
http://wiki.project1999.org/index.php/Skill_Make_Poison
"
you rarely fail to apply a poison you can make, but the higher your apply poison skill the faster you can get the poison on your blade and stand back up..."
Not sure who wrote it but maybe he played a rogue on live, I don't know. Point is it doesn't make sense to be failing to often.