Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
  Case Tag  
Price  
Sales  
Tax %  
Raw Total  
Incl. Sales Tax  
Rounded  
to Penny  
Rounded  
to Nickel  
Rounded  
to Dime  
  Purchase #1 $86.81   10.239%   $95.6985   $95.70   $95.70   $95.70  
  Purchase #2 $163.56   13.789%   $186.1133   $186.11   $186.10   $186.10  
  Purchase #3 $163.76   7.658%   $176.3007   $176.30   $176.30   $176.30  
  Purchase #4 $212.96   10.672%   $235.6871   $235.69   $235.70   $235.70  
  Purchase #5 $125.86   5.449%   $132.7181   $132.72   $132.70   $132.70  
  Purchase #6 $222.78   3.808%   $231.2635   $231.26   $231.25   $231.30  
  Purchase #7 $120.98   12.602%   $136.2259   $136.23   $136.25   $136.20  
  7 purchase totals = $1,096.71       $1,194.0071   $1,194.01   $1,194.00   $1,194.00