Technically you *should* be able to do something like the following:
Code:
foreach pick in hero from Tool where "thingid.gTooThieve"
eachpick.field[Bonus].value += 1
nexteach
as long as your timing is right, it *should* do the trick. (usually post-level 10000 and before Calc skProfBon works for tools and skills).
It doesn't and I'm not sure why. If you right-click the tool skill in your list and look at field histories you can see that a field called "actName" is updated at Render/30000. This is a LW side script that we can't look into, but I'm going to guess that the name that gets generated isn't looking at any bonus or penalty fields.
It might be worth the time to open a trouble ticket with LW to see what's happening and if it can be modified.
Tool proficiencies are weird.