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	$196.58	10.556%	$217.331	$217.33	$217.35	$217.30
Purchase #2	$95.99	10.674%	$106.236	$106.24	$106.25	$106.20
Purchase #3	$54.90	8.503%	$59.5681	$59.57	$59.55	$59.60
Purchase #4	$140.98	12.592%	$158.7322	$158.73	$158.75	$158.70
Purchase #5	$104.96	13.755%	$119.3972	$119.40	$119.40	$119.40
Purchase #6	$201.30	7.505%	$216.4076	$216.41	$216.40	$216.40
Purchase #7	$71.75	8.768%	$78.041	$78.04	$78.05	$78.00
7 purchase totals =	$866.46		$955.7131	$955.72	$955.75	$955.60