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	$72.84	4.525%	$76.136	$76.14	$76.15	$76.10
Purchase #2	$57.66	5.437%	$60.795	$60.80	$60.80	$60.80
Purchase #3	$111.83	4.525%	$116.8903	$116.89	$116.90	$116.90
Purchase #4	$108.57	7.416%	$116.6216	$116.62	$116.60	$116.60
Purchase #5	$161.46	4.117%	$168.1073	$168.11	$168.10	$168.10
Purchase #6	$201.94	10.462%	$223.067	$223.07	$223.05	$223.10
Purchase #7	$245.58	3.628%	$254.4896	$254.49	$254.50	$254.50
7 purchase totals =	$959.88		$1,016.1068	$1,016.12	$1,016.10	$1,016.10