Hi Dubious,
Good observations
Thanks for playing.
the amber/white is for ease of reading across the columns.
red text in the com. ex. means "shortage" ; that commodity will be very profitable to sell there, and impossible to buy.
blue text means 'surplus', and you can buy it for cheap.
Prices change over time, and if the prices go to "?", it means that your information is out of date, and prices on that commodity have changed.
The rate at which prices change is (hopefully) balanced between "being able to find an exploitable route" and "not being able to do it forever".
Trading was never intended to be a primary early-game tactic, but it seems players have embraced it. Always accepting feedback,
Bob