In general, if you want to revise and resubmit any assignment within a week after it was due, I will regrade it (eventually–perhaps not immediately), and average the new grade with the old. So if you get an 85= B at first, resubmit and get a 95=A, then I will record the grade of 90=A-.
However, the maximum achievable grade upon resubmission is a low-A, in my numerical scheme, 92.5. In other words, it will not pay to resubmit an A! I think this is appropriate.