My item valued at 100 caps sells for 110. Why? (Bonus Question Inside)

[NexusElder]

I've been working on modding the way commerce goes on in the Commonwealth, primarily centered on player perks and what few game settings I could find.

 

In order to test the mod, I'm tracking the buy/sell ratio of an item (10mm Pistol, no mods), which I've also modded to have a value of 100, while the player levels their skills. Though not the end of the world, I've hit a snag (see title). I'm about as novice as they get, but this is what 2 days of head-scratching has gotten me so far:

 

At first I thought it was having Charisma 1 grants an extra 10% value, but tuning base charisma doesn't seem have any effect on the value of my items.

Then I thought it was the PlayerPerk, which has a few mod Buy/Sell entry points, but yielded no results after deleting them.

 

This extra 10 caps appears to be 10% of the base value, as changing it to 50 makes it worth 55. My question is thus: where is this extra 10% coming from?

 

Bonus Question: fBarterMax appears to change both Buying and Selling power, and fBarterMax appears to do nothing. Am I missing something, or is this just poor implementation? Any knowledge you can share on fBarterMin, fBarterMax, fBarterBuyMin, fBarterBuyMax, fMinBuyMult, fMasSellMult, or any other relevant settings or files I have missed would be immensely appreciated