Am I REALLY salaried?

I have been employed for a CPA firm for the last 2 years, as an accountant on a salary basis. My checks are twice a month the same amount, regardless of hours worked. However, if I work overtime, I get comp time - hour for hour. If I don't work, I have to use vacation time. If I don't have enough comp time or vacation time, I go negative and have to work overtime to pay it back or if I were to quit would have to repay the hourly equivalent. During tax season, I am paid my hourly equivalent + $5/hr (not the OT rate) for hours of overtime. It seems to me that if I were truly salaried (exempt), if I work more or less I would get paid the same regardless. It seems like they have these rules to benefit them and not have to pay time and a half. My questions are: 1) Why even have 'vacation time' for salaried employees?, 2) Am I thinking right on this, that I would probably be better classified as hourly, 3) If yes, is there something I can bring to my employer that would outline these issues (so far all I'm finding is that based on job description I would be exempt, but not any other requirements such as actions that define what status I am), 4) Should I go back and calculate all the overtime and present it to my employer, and if so, do I count the 'comp time' used?

Any guidance is appreciated!
Thanks.