It seemed to me that this wasn't quite important enough to merit a "Support ticket" so I'm just dropping it here.
I suggest that
1) Y'all make sure the rules at https://panel.talonro.com/rules and the rules at https://wiki.talonro.com/Server_Rules are perfectly homogenous, for ease of reference, and
2) Y'all clarify that the buying-store rule as listed in the Server Rules etc does in fact have the caveat mentioned in https://wiki.talonro.com/Buying_Store, namely that the "NPC Value" referred to does not take into account overcharge.
The wiki is just a thing that can be edited by "All members of the community" after all, so the entry in "Buying store" on the wiki mightn't be as authoritative as something listed in the hard rules themselves : D