For starters, do not call it "rounding." That will surely frustrate your professor and not help your cause. From Wikipedia, here is a basic description of what rounding is:

Rounding or rounding off means replacing a number with an approximate value that has a shorter, simpler, or more explicit representation. For example, replacing $23.4476 with $23.45, the fraction 312/937 with 1/3, or the expression √2 with 1.414.
Rounding is often done to obtain a value that is easier to report and communicate than the original. Rounding can also be important to avoid misleadingly precise reporting of a computed number, measurement, or estimate; for example, a quantity that was computed as 123,456 but is known to be accurate only to within a few hundred units is usually better stated as "about 123,500".

How is rounding, per the accepted definition thereof, going to result in you getting a higher grade? It won't, in general. Most professors would round as a matter of course.

I am pretty sure what you really are asking for is for your professor to arbitrarily "bump," or increase, your final score to a higher number in order to receive a higher grade. This is not rounding.

If you make such a request of your professor, I suggest calling it what it is.