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	$196.42	7.406%	$210.9669	$210.97	$210.95	$211.00
Purchase #2	$100.57	4.654%	$105.2505	$105.25	$105.25	$105.30
Purchase #3	$203.94	9.773%	$223.8711	$223.87	$223.85	$223.90
Purchase #4	$222.60	6.344%	$236.7217	$236.72	$236.70	$236.70
Purchase #5	$139.45	9.458%	$152.6392	$152.64	$152.65	$152.60
Purchase #6	$181.77	3.364%	$187.8847	$187.88	$187.90	$187.90
Purchase #7	$132.87	9.229%	$145.1326	$145.13	$145.15	$145.10
7 purchase totals =	$1,177.62		$1,262.4667	$1,262.46	$1,262.45	$1,262.50