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	$217.60	7.393%	$233.6872	$233.69	$233.70	$233.70
Purchase #2	$60.62	7.154%	$64.9568	$64.96	$64.95	$65.00
Purchase #3	$29.66	8.382%	$32.1461	$32.15	$32.15	$32.10
Purchase #4	$54.54	3.197%	$56.2836	$56.28	$56.30	$56.30
Purchase #5	$96.51	9.259%	$105.4459	$105.45	$105.45	$105.40
Purchase #6	$157.52	7.727%	$169.6916	$169.69	$169.70	$169.70
Purchase #7	$67.43	5.849%	$71.374	$71.37	$71.35	$71.40
7 purchase totals =	$683.88		$733.5852	$733.59	$733.60	$733.60