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 $87.27   8.855%   $94.9978   $95.00   $95.00   $95.00  
  Purchase #2 $194.93   10.535%   $215.4659   $215.47   $215.45   $215.50  
  Purchase #3 $80.71   6.699%   $86.1168   $86.12   $86.10   $86.10  
  Purchase #4 $48.96   9.443%   $53.5833   $53.58   $53.60   $53.60  
  Purchase #5 $204.66   5.600%   $216.121   $216.12   $216.10   $216.10  
  Purchase #6 $189.74   8.256%   $205.4049   $205.40   $205.40   $205.40  
  Purchase #7 $127.54   4.620%   $133.4323   $133.43   $133.45   $133.40  
  7 purchase totals = $933.81       $1,005.1220   $1,005.12   $1,005.10   $1,005.10