My A/C hasn't been able to keep up with the heat lately (it's been in the high 90's with high humidity, and today the house was up to about 82 inside even though it's set on 70). I went up into the attic a few minutes ago to see if my untrained eye could see anything wrong with the unit, and I noticed two things:

1. There is a hissing noise coming from the unit where the refrigerant lines go into the evaporator. I know that I have a TEV, and I've read online that these can sometimes hiss, but I wanted to see if that's likely what the cause is or if it's possibly something else.
2. Cold air (quite cold) is blowing out of the hole where the refrigerant return line comes out of this box (this is also where I'm hearing the hissing), and the attic was cooler than the rest of my house!

I just had a popular local A/C company out here to investigate, and he said that the unit appeared to have been undercharged from the time it was installed (the house was built in 2006), so he added two pounds of refrigerant. He said that he didn't find any leaks. Are either of these things issues?