I'm not there so unable to advise with confidence. I will tell you that it rarly takes me longer than 2 hours to clean A coils in place. This effectivly cleans coils 90% of what is accomplished by removing them. The price quoted for new equipment looks reasonable.

My first question would be why is coil clogged. Clogged from what? No filter protection? What is condition of furnace blower motor?

You need a second opinion on problem as well as your options and pricing. With just a new coil, chances are you will have a mismatched system. Probably will work just fine. But just so you know. Purchase though of new coil should be looking toward future for a new system.

IMO

The tech says says the plugged coil comes from dirty filters. We built the house and have been the only homeowners. 99% percent of the time the filter was changed regularly so I have my doubts. It's the same company that installed the system giving me the quote now. Yesterday morning the house was 56 degrees when I woke up. Today it's 69 in here. The outside temp hasn't changed enough to account for the difference so something he did in the two hours he was here helped somehow but the paperwork doesn't reflect any repair performed. I have a service and protection plan so some repairs he could have performed would have been under the service agreement but I think they would still be mentioned in the paperwork for the call.

2nd opinion is strongly indicated.

Third party warranties/service contracts are usually worthless and work performed are by HVAC hacks.

Something highly suspicious here.

IMO

"Technician came out and spent two hours looking it over. Finally tells me he thinks it is the "A" coil."

It took two hours to diagnose the problem and he is not sure if it is the correct fix? Cut your losses and hire someone who is competent.

"I have a service and protection plan"

So why are they charging you for repairs?

They say the dirty coil is due to bad maintenance (not changing the filter often enough) which makes the protection plan void.

Nothing but a scam...

Drop this company and find a reputable dealer who will diagnose and give you options.

Plain and simple, don't trust the company you are dealing with.

IMO

That's more than likely what I will do. I have someone coming to give a second opinion in the next couple of days.
To be fair to the company (not that I've named them) the service plan has covered a couple of repairs & 2 cleanings a year (which I didn't schedule due to having brain surgery and recovering from brain tumor removal in the last year) which would have cost me more than I've paid into the plan over the last 2 yrs. It's not a third party plan but through the company that installed the system when we built the house. I always felt pretty confident in their honesty and abilities but now not so much.
Our outside temps have raised 20+ degrees since Monday and the house is staying at the set thermostat level of 70 but we're supposed to have cold temps return over the weekend so we shall see how it performs then. I'll let you know what the second opinion is.
Thanks for everyone's advice!!!!

BTW: forgot to answer tigerdunes question on blower motor. The tech showed me that it is black with dust on the inside. The blower motor was replaced a little over a year ago by the same company.

If the blower was indeed A. Changed 1 year ago with squirril cage and housing cleaned during replacement B. Now covered with lint and dust only 1 year latter, without doupt the air is not being properly filtered. Frequency of filter changes is only 1 out of 3 considerations in proper maintainance. Proper fit and filter type are the other 2 leggs on the subject. The 99 cent fiberglass filters are barely better than non at all. When and if you install a new air handler,insist on the largest filter rack possible that uses a common size filter and use pleated filters. I have inspected many new installs that had a poorly fit filter. When asked how the customer is suppused to maintaine filter changes the stock answer is "they can order them custom made through a supply house." Custom made filters are at minium 4 or 5 times the price of same material in standard sizes.