Making cupcakes for my Alice in Wonderland book report i used two boxes of cake mix for times sake. The first box of cupcakes turned out decent but the second box came out really flat and didn't rise much. I had to bake them in two sets because i didn't have enough muffin cups to make them all at once. I let the muffin tins cool after the first batch and filled the same sizes cups with the same amount of batter (i used scoops) but the second batch did not rise as much. Is it possible to over beat the batter? I tried an experiment and beat it about twice as long as it said to because the batter seemed awfully tnin. It could just be it was old mix. Any thoughts?