The Home inspector determined that input of air and output air was not balancing and that we should have a technician inspect it. We had the seller address the air conditioning issues in the BINSR. During the final walk through, we went to visit the property at end of day, it was a hot day, the air conditioner was set to 86 degree. It took 2 hours for the air conditioner to cool down 2 degrees, the buyer was not happy and she was threatening to cancel the contract in the last minute. To remedy the situation, we scheduled technician to inspect he air conditioning issues on the day of closing.
The final result was that the air conditioner was working just fine. The reason that one of the rooms was warmer because it had only one duct in the room, the second reason was that it took the air conditioning longer to cool because the air had to travel a longer distance and the ducts were narrow, it could only carry so much air.
Other houses with same issues, were that one of the ducts output varied to the next. The solution to my house was that, we needed larger air conditioner to be able to put out enough air to cool all the rooms.
Finally, when the inspector says that there may be issues with the air conditioning output; do not panic, their is always a reasonable explanation to the problem.