I had a new infinity 16 seer 4 ton 2 stage v/s heat pump put in my 2000sq foot home in Dallas Texas. The company did do a manual j test. The only problem I am having is the master bed room is still warm. It is the furthest room from the unit. The run is about 40ft long. When the unit is on high it cools the room fine. When it is on low the room gets warm. The unit runs on low 2/3 of the time, so the room is warm 2/3 of the time. The other parts of the home is fine, any suggestions?