Swamp, you do make a good point about calling an HVAC tech. Sort of a "damned if you do, damned if you don't". I inspected a home a few months ago and got a 7 degree split on the A/C, I recommended calling HVAC, they came out and said everything was OK, the system was working fine. Needless to say, I got a call from the pissed homeowner demanding I pay the $65 service call. Funny thing is, it was a company that I had called out a bunch of installation problems on other recent jobs. Its all judgement calls I "gues".