I just read the article on irowiki :
There's a part that I found interesting :
The iRO website suggests that certain NPCs will have a better chance of slotting different level weapons or different types or armor. It is unclear whether this reflects game mechanics, and no large samples are available. The increase is rumored to be on the order of 5%.
Does anyone have a confirmation, or at least some information about this ?
I don't remember seeing anything official (or even testing results for that matter), but the general thought was that you have a better chance if you're in the appropriate town for the item. e.g.: you should slot bows and tights in payon, wands in geffen, etc.
What is a Mega Man?
A miserable little pile of mega secrets!-JCvgluvr
According to eAthena NPC scripts, they don't have any difference in them, the other town's NPCs are just duplicates of Payon's.
Bu then again, eAthena isn't 100% accurate.
You don't need a reason to help people.