Wow, a lot of information in the first page... that does not happen often. I think the HO here is taking a pro-active approach here, I agree.
Lets see if I can unravel some of this, even though my company is not a Goodman dealer (we do Ruud, but do a lot of service on Goodman because the builders use them a lot). I will try to address as much in the thread as I can.
First lets look at your questions:
1) In my early years in this business, I repaired a lot of coil leaks. I learned that repairs tend to work better with outdoor units than evap coils, so mostly I repair outdoor coils only. Most of the time (my experience) evap coil leaks are due to 'dis-similar metal corrosion' (copper, aluminum, and steel in contact with each other in a wet environment). A coil replacement is a common repair.
2) IMO replacing the AH would not be a good approach. The reason the new AH is cost competitive is that the new AH will be 13 SEER. The old coil probably is out/production (10 SEER). And grafting in a 13 SEER coil is tricky due to size issues. Also a HP, because it works both ways (cooling and heating), is more sensitive to coil matching to the outdoor HP.
On this replace the AH topic, we are kinda at a turning point in the industry: R-22 equipment goes away (not the refrigerant, the equipment) on Jan 1, 2010. So a replacement R-22 HP may not be available down the road. As far as flushing and converting to R-410; my product line does not support that approach. Yeah, it is a tuff place to be...
3) I am sure every HVAC guy wants to do a new install. It is kinda like the 'hole grail' of the business... While there are advantages to a new system, it may or may not be the best road to go. A thorough evaluation of your ENTIRE current installation would equip you to make that decision... And IMO a contractor that would spend the time with you to do that would be a good person to consider to do whatever work you choose to do.
You see; in the HVAC world installation is waaay more inportant than equipment. The best equipment, installed poorly, will not work any better (sometimes worse); than average equipment installed properly. The things that need to be done to do a quality installation both take more time, and require more expensive equipment (tech tools) to do. Thus, a quality install costs more, depending on the overhead structure of a company.
Personally, I got a chuckle out of the circuit breaker story... I understand your concern. We all have 'those days'... but a person that will admit it is in my book a better person than one who dodges it. Just my personal opinion.
Now lets go to post #11. There is a weath of information here, lets see if we can make sense of it:
Some folks charge a bundle for leak checks, some charge less. One thing about injecting dye into the system is that an effective dye check requires a second visit the next day. I am not a fan of dyes because it adds an extra chemical to a place where contamination is a critical issue. Not that all dyes are bad, but clean is better IMO.
Frost on a coil is most of the time either low refrigerant or airflow issues. A qualified tech (or company owner) could do a thorough diagnosis and find a few more details to come to a conclusion as to problems. And yes, if there is frost on a coil, or a problem with condensate draining out the proper way; the humidity will go up in the space.
Hey, you and I are in the same area! I really am enjoying the early fall weather this week!
It would not be ethical for me to speak highly or lowly of other HVAC folks in particular. In general, my opinion is that an experienced tech (or company owner acting in a tech position), would be able to do a more thorough diagnosis.
Refrigerants go up and down with the season (demand). But looking at it in a long term view; I think up (maybe slowly) is the trend for R-22.
HP's run the compressor a lot more than A/C, becuase they use it to heat as well as cool. Thus, a HP tends to not last as long. A general 'fair' life of an A/C system is 12-15 years, more if maintained properly, less if neglected. HP's tend to be less.
I may be wrong on this one, but I kinda doubt your HP (or AH) has a TXV valve.
Sounds to me like you are careful to take care of the filters. That is the one most important thing a HO can do (themselves) for their equipment.
Most 'builder' installations I look at are a little short in proper ductwork. Many customers have me do some duct modifications to improve air flow and efficiency.
OK, now for my advise: As others have suggested; get another person out to look at it. As I mentioned above, a seasoned tech or company owner acting as a tech could do a thorough evaluation and present you with data to make a decision. Expect to pay some $$$ for this, we do not give it away free (we have spent many $thousands on education). And IMO, a company with seasoned techs (or a small company where the owner is there at the tech/install/sales/service level might give you better customer service).
There, I hope I have given a fellow Atlanta resident some solid guidance.
Let us know how it turns out.