I am not a Goodman dealer but if I read that Sr# correctly 0411 was manufactured November 2004. If I am wrong the others will correct me.
Not to throw a monkey wrench into the gears but did the builder offer you a higher SEER unit. In your area and with 10 Seer on its way out I would have thought so???
no upgrade offered
My builder never offered me a SEER upgrade. if so i probably would have takin advantage of it. I heard for my area starting in 2006 in new construction homes a 10 SEER will no longer be used. 13 SEER will be lowest.
Its not just your area and not just new construction. As of January 2006 manufactures cannot produce 10-SEER equipment. With that being said get the extended warranty for your unit.
I still recommend getting a second opinion on this system. Builders and HVAC contractors will cut corners wherever they can just to save a buck.
Go buy yourself a digital humidity meter at WalMart. Your problem could be as simple as low air flow. If the air flow is low the air conditioner will expend more of its energy removing water from the air, leaving it with less energy to cool the air.
When the system runs for an extended period the humidity should hold at around 50%. If it goes much lower than that your system is wasting energy removing water from the air.
But if you change the air flow on a system without a TXV you will have to have the charge adjusted to ensure decent performance.