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	$191.51	13.581%	$217.519	$217.52	$217.50	$217.50
Purchase #2	$10.56	4.293%	$11.0133	$11.01	$11.00	$11.00
Purchase #3	$54.37	13.867%	$61.9095	$61.91	$61.90	$61.90
Purchase #4	$173.50	10.225%	$191.2404	$191.24	$191.25	$191.20
Purchase #5	$193.26	13.777%	$219.8854	$219.89	$219.90	$219.90
Purchase #6	$236.39	5.236%	$248.7674	$248.77	$248.75	$248.80
Purchase #7	$99.47	6.857%	$106.2907	$106.29	$106.30	$106.30
7 purchase totals =	$959.06		$1,056.6257	$1,056.63	$1,056.60	$1,056.60