Not sure if you have this resolved, but I would warn that altering the output value of a created poison could change skill progression points. I'm working on an Alch mod myself, the way I got it set up, the skill progression disappears. After doing a bit of research I found that the actor values (in the character pull-down window) houses an Alch actor, the name of which I forget. But basically what it is, is a multiplier whereby your alchemy skill increases at a percentage of the value of the potion that you create. So if the Actor value was 0.6 (aka 60%) and you created a potion worth $100 (or septims or whatever) then you would gain '60' Alchemy sub-skill points (0.6*100=60). Get enough of what I call "sub-skill" points and you earn an actual in-game alchemy skill point (you can actually watch these little sub-skills grow, there's a little bar underneath the perk category name "alchemy" in the SUPER-GALACTIC perk menu. So if you decrease the overall value of a potion/poison to incentivize the most expensive (in skill points) perk, it will take that much longer to actually earn it. Unfortunately the CK does not let us alter the behavior of these actors, if we could (and/or I could understand this crazy scripting language), I would have already released what I think would be a badass alchemy mod.