Thanks for the speedy response! I went back and watched the videos, and I was indeed purling the wrong way. The funny thing is that I was bringing the yarn under the needle regardless of the hand holding the yarn. Maybe I just imagined that the right handed purls looked better.
I've done so many projects with purl stitches - it's a wonder I never noticed this.
So now I have an interesting dilemma. There's a big section at the top of the sweater that I want to redo. Can you unravel from the top to save the remainder of the piece? All the discussions about frogging I've seen talk about unraveling from the bottom.
Thanks again for the help.