Invoice Rounding Issues

Is anybody else dealing with Rounding Issues. I have an Example here
that I am using to try and fix the problem.
I have an Item I ship 3 lots of 9789 pieces at a unit price of .3186
So it is a total of 29367 Pieces * .3186 = 9356.3262
I then Add my Misc Charg of 452.25 and Get a total of 9808.5762
That would be an extended price of 9808.58
But Vantage Tages Each Lot of 9789 * .3186 = 3118.7754 Then Rounds it to
3118.78 and Multiplies it by the 3 Lots to = 9356.34 + My Misc Charge
of 452.25 = 9808.59
So I get 9808.58 But Vantage Gets 9808.59
Not sure what to do?