Potion exchange would require some upgrades. Currently it looks like all
potion exchanges are individuals, it could work like material/reagent
exchanges and Potion exchange module could be available also for pcities.
There aren't that many potion makers, so 5 potion limit is bit harsh, or what
counts to that limitation should be changed. Currently it seems to take
different colored potions in to account and actually same colored potions also
can count as different potions. So could the limit make 5 different
potions(spells/skills).