Oh, I figured out how it's doing the calculations. If I buy the item and look at it in my inventory, its value is 60. 30% of 60 is 18. 150-18 is 132 (influence would further reduce the price to 131). But then, if that's the case, if bartering is a percentage of the base value of 60, shouldn't it be applied to that base value before being scaled up 250% for sale by the NPC? That's what I would expect. I mean, the description of bartering says "Traders will drop 10% off their base prices."
