LoL same thing with me, switched from lights to ultra lights and i think i smoke more now..
However i am quitting soon, i am thinking after my exams at college 3 this week, and i cant even imagine going through them without my dear cigs.. but if i did quit b4 exams and succeeded in my exams.. i think my motivation and confidence to quit would go through the roof !
I wouldn't try quitting while in your exams. It works badly both ways, the stress from exams make you more likely to give in to the cravings, and the cravings will take your focus of your exams.