Hi there @Carik
Your assumptions are pretty much ‘nail on the head’. There are currently 650 Trade Commodities in the game. These are spread over the dock-able locations. As you have stated there is a static trade in these TC’s in each location, however stock values are affected by a number of things.
Stock values and amounts will rise and fall dependent on normal stock market fluctuations (withing a given set of boundaries). They will always bounce back to their default setting eventually though. They are also affected by player habits, IE if players continually run a stock dry this will affect its market value not only there but in other locations. This is not an ‘immediate affect’ but one over time.
EACH location has its own ‘base’ value and stock level for TC’s which are then modified by the above settings. So the price for say ‘Anthropological Exports’ can vary across locations. Currently there is a variance in that TC of a 236 credits across Seven locations in game.
Hope this verification helps somewhat.