HI: Recently had my Carrier 38YZA heat pump serviced. It was still cool enough here(south eastern Ontario) that the heat pump was in heating mode. The tech and his apprentice did the usual things like pressure washing out door condensor etc. They hooked up the gauges and to check pressures. They felt it needed a smidgen of 410A. After that I didn't run the system for week and a half until the weather turned much warmer and much more humid. The heat pump went into cooling mode when I fired it up. That's when the problem started. The compressor started to cycle off and on and the unit had trouble bringing the temp down to set point. I believe the compressor was going off on high pressure. Called the company again and they sent a different tech. He said the pressures were not right for cooling. He played with adding more refridgerant, but stated he didn't want to put too much in and would rather have a little less, then too much. He also said he didn't know very much about the system I have Carrier 38YZA and FV4A Fan coil. So they sent a different tech over to check it out. He determined it was the TXV that was shot. They replaced it today and they had the system running for about 20 mins and seemed ok. They charged me 3.5 hours labour to change it. Does this all sound reasonable to you guys?