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	$162.25	7.548%	$174.4966	$174.50	$174.50	$174.50
Purchase #2	$172.81	7.648%	$186.0265	$186.03	$186.05	$186.00
Purchase #3	$189.49	10.136%	$208.6967	$208.70	$208.70	$208.70
Purchase #4	$38.63	11.548%	$43.091	$43.09	$43.10	$43.10
Purchase #5	$55.98	6.778%	$59.7743	$59.77	$59.75	$59.80
Purchase #6	$177.89	10.317%	$196.2429	$196.24	$196.25	$196.20
Purchase #7	$86.70	9.665%	$95.0796	$95.08	$95.10	$95.10
7 purchase totals =	$883.75		$963.4076	$963.41	$963.45	$963.40