Problem! first grow. HELP!

So I thought about two weeks ago that I over-nueted my plants, or they were heat stressed because the leaves were curling under at the tips and I saw some yellowing on some lower leaves. I leached the soil of all the plants to make sure I got all the nuets out and since I have not gave them anymore. I checked all my temp and humidity gages and everything is good as always. The leaves havent went back to normal. Will they? I am not even sure if they are suppose to but I assume so. I have read my grow bible over and over and keep thinking what it could be, today it hit me. My plants are in half gallon, to a gallon pots right now. And are over a foot tall. Do you think it could be that they are in to small of pots? and can't expand and it may have caused some of the plants leaves to curl under? Not all the plants have this, only half or so. Other plants are fine and have all grown fine. Just recently I noticed my new clones are growing at a much higher rate then the ones that have been vegging for a while (1 month 2 1/2 weeks). Do you think I should transplant now? Is that the problem? INPUT WILL BE THANKFUL. ANYTHING!

Here is the link to my prior post w/ pictures of the plants and what some of the leaves looked like - HID Light Burn? Over Nuet? Leaf tips curling down, yellowing!?!

your gonna have to repot anyway might as well do it now