OK I think this is very unfair.
For example, I play as Teuton. My traders are slowest. Can't wait to build Trade Office level 10 so I can have 2k ress per merchant. Even that I do not find enough but what you gonna doo...
Then I go play Roman or Gaul and LOOK SURPRISE. Even if their merchant are 2x faster (gaul) they get each carry capacity with each Trade Office.
Which each level you can haul 100 ress more. So Teuton lvl 10 trade office can haul 2000 but roman can haul....check this out: 1500. Gaul can onlvl 10 trade office haul 2250, And it is super fast.
And trade office resource cost is same for each Tribe.
This is very very unfair and I have just seen this.
Roman and Gaul traders are overpowerd lookin at Teuton. On lvl 20 Teuton can carry 3k ress, Roman 2500 and Gaul 2750.
I see math differtnt then most people. And when I see that Teut merchant is actually worst and most expensive on level 20 trade office...
I suggest that each level gives 10 percent more (100 for teuton, 50 for Roman and 75 for Gaul). Regarding speed, that would be more then fair!