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 $182.26   7.513%   $195.9532   $195.95   $195.95   $196.00  
  Purchase #2 $227.53   6.266%   $241.787   $241.79   $241.80   $241.80  
  Purchase #3 $73.99   12.668%   $83.3631   $83.36   $83.35   $83.40  
  Purchase #4 $55.96   6.585%   $59.645   $59.65   $59.65   $59.60  
  Purchase #5 $240.58   5.844%   $254.6395   $254.64   $254.65   $254.60  
  Purchase #6 $196.95   13.316%   $223.1759   $223.18   $223.20   $223.20  
  Purchase #7 $207.57   5.524%   $219.0362   $219.04   $219.05   $219.00  
  7 purchase totals = $1,184.84       $1,277.5999   $1,277.61   $1,277.65   $1,277.60