To the OP. The TXV will not be your problem it will still flow the correct refrigerant since it is looking at superheat. If it is drasticly oversized it can cause hunting which can make capacity and efficiency fall a bit but not have anything to do with your short cycling. If Carrier said that the match is fine then it is fine. If on the other hand you had an undersized valve then you would not be able to handle full loads as well.
I think the right thing to do is to verify the airflow. If you are geting too much airflow you may actually increase the sensible capacity of the system which will satisfy the stat slightly faster. You may also watch the temps at the stat with a digital thermometer to verify you do not have a supply air register blowing on the stat which would also cause short cycling. Then consider the sizing with a manual J.