Some things that author might have missed. The up arrows on the trade screen means the prices of those commodities are going up. Also, I believe the upgraded trade ports function as a multiplier. For example, if I have 25 barrels of tea at a region that has a trading port with 2 export routes, I'm exporting 50 barrels. I haven't tested this fully but it seems to be correct. I'm not sure how multiple trade ports affect it.