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	$196.89	13.565%	$223.5981	$223.60	$223.60	$223.60
Purchase #2	$10.65	5.563%	$11.2425	$11.24	$11.25	$11.20
Purchase #3	$48.39	7.453%	$51.9965	$52.00	$52.00	$52.00
Purchase #4	$65.52	4.408%	$68.4081	$68.41	$68.40	$68.40
Purchase #5	$132.49	6.116%	$140.5931	$140.59	$140.60	$140.60
Purchase #6	$209.72	7.363%	$225.1617	$225.16	$225.15	$225.20
Purchase #7	$123.89	13.399%	$140.49	$140.49	$140.50	$140.50
7 purchase totals =	$787.55		$861.4900	$861.49	$861.50	$861.50