Well, I myself am not quite sure what should one turn REALLY last. Especially regarding troops movements. But in general troops movements are increased, they can definitely move more than one old 'province' per turn.
You will get your stats on email, a new redesigned one, so you will get better idea of this commerce limits.
Commerce limit presents your ability to support growing population and economy. It is primarily food based, but also represents infrastructure, population etc. It can prevent growth of economy if you haven't built a suitable base for it.
In general, cities provide 15 commerce limit points, farms 15, fisheries 10, health buildings and resources provide more... That is your limit. Usage of this limit is determined by formula (excel calculates this for me):
( (Income from cities)+(Trade income / 2)+(Upkeep and maintenance * 2) ) / Your stabiliy * 100
So if you earn 30 gold from cities and 10 from trade and waste 2 to upkeep military, and have 100 stability, you use (30+5+4)=39 commerce points. If your stability fell to 50, you would use 78 points.
If your usage goes over capacity, you face production shortfalls, supply shortages, food price increase, or even mass famine. So be aware. Exceeding limit will risk you bad events, that cost you gold and stability, and may cause civil unrest. You will also lose a gold coin for every point you exceed your commerce limit.
Even staying close to your limit is not a good idea as limit can fluctuate- harvests can never be completely relied upon, and you do not want one bad harvest, storm or locust swarm starving your people - leave a bit of excess food.
If you notice that your commerce limit is bad, do not despair, as this rule won't actually come in effect until 2 turns for now, so you have time to build farms, feed your population and get economy in check.
Trading of excess commerce limit will probably be allowed as well, but it will either be at low efficiency (2 economy points for 1) or use a trade route.