I'd say that there was definitely some difference in tension, and that has bowed the neck. However, you should definitely check to be sure, either sight the neck or use the string as a straight-edge to see if there actually is a bow (unless you've already done this and it is confirmed, that is!).
From the info you have here, I'm guessing you're right, you need to put a little more tension on your trussrod.
Feel free to give me a shout at the shop (not today, of course!

) if you have any questions:
336.274.8810