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	$230.39	4.678%	$241.1676	$241.17	$241.15	$241.20
Purchase #2	$56.62	4.814%	$59.3457	$59.35	$59.35	$59.30
Purchase #3	$26.62	6.330%	$28.305	$28.31	$28.30	$28.30
Purchase #4	$184.27	3.519%	$190.7545	$190.75	$190.75	$190.80
Purchase #5	$126.54	11.705%	$141.3515	$141.35	$141.35	$141.40
Purchase #6	$226.35	6.601%	$241.2914	$241.29	$241.30	$241.30
Purchase #7	$100.70	11.403%	$112.1828	$112.18	$112.20	$112.20
7 purchase totals =	$951.49		$1,014.3985	$1,014.40	$1,014.40	$1,014.50