According to my understanding those big and small import/export figures are caused by the order of players although obviously you need to have many OBs as well. Whoever is first in the list has a big negative value as other civs choose first X-commerce routes provided by him and then select the routes from 2nd player in the list and so on.. If you are the last one in the list you get a big number, because everyone prefers connection to other players if the yield is the same. I'm not sure how or how often this order is determined in Pitboss, in PBEM it's just a turn order. However, if you have more trade routes per city than your opponents it also leads to positive values and thus OH's guess makes sense, but it's not impossible that plako or mack is rival worst either. In PBEM45G Sareln had built the GLH and everyone had OB with everyone, but because he was first in the turn order his export/import value was by far the lowest.
Re actual game stuff: Let's see if Ichabod's navy will be our doom... This is the price we need to pay for our invasion and it was to be expected.. Ice is thin once again
The positive thing is that Ichabod's teching has actually been surprisingly weak and it's great that we had so much time before he was able to build his first frigate, captured cities are coming out of revolt and they will have a major role in the production of our western navy. Aaand Ichabod should not be too close to combustion yet.. 
Re actual game stuff: Let's see if Ichabod's navy will be our doom... This is the price we need to pay for our invasion and it was to be expected.. Ice is thin once again
The positive thing is that Ichabod's teching has actually been surprisingly weak and it's great that we had so much time before he was able to build his first frigate, captured cities are coming out of revolt and they will have a major role in the production of our western navy. Aaand Ichabod should not be too close to combustion yet..