Don't do the duty of 8 hrs... our case was almost same, though our one said of 7 hours, telling him was of no benifit, though i tried once, but failed, 

what i did then, always late in the morning, 30 to 40 mins late, and leaving the office at sharp timing, three days i did it, then other two guys also followed the same thing, now timing is of six hours, but now i only leave on exact time, not even a single minute late,

and about the accountant, don't think about these guys, the shoe licker of the company, giving some benifit to the company by not giving OT, cutting salaries of the labors, so manager always like them...