Joe,
The freezing up is also caused from low freon. Yo may have been low on freon last year but had enough that the system would still run. But this year it shut down. Think low
oil shut down on your engine. Sorta works the same way. Two pounds of freon is all that system will hold so you basically had none.
Now, (not getting smart here OK, just trying to help) What makes you think just putting freon in will solve the problem? It will not. The guy that put the freon in should have suggested you have a leak test performed. My Lord that is good money for them so why would they not do it, ESPECIALLY if the unit is not in the hot attic. The only thing I can think of is, since the guy that actually came out to your house is NOT the guy they first called, they are having service problems with their "main" A/C company. My guess would be lack of payment from the builder for other jobs.
Meritage is all over the papers about the troubles they are having. They have sooooo many new developments right now and no buyers, so the market conditions are getting tough, even for the big builders.
The time frames of Morn, midday and evening are OK. Stick with your story as you know it. You may want to stop and make a time log of what happened while it is still fresh on your mind. You simply have to follow through though.
I assure you that if you don't get a leak test done and the problem fixed you will have to go through this next year. You have to fix the problem not put a band aid on it.
I know I am not looking forward to 100* today. Texas is too damn hot in the summer.