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	$196.54	6.325%	$208.9712	$208.97	$208.95	$209.00
Purchase #2	$204.27	10.500%	$225.7184	$225.72	$225.70	$225.70
Purchase #3	$160.28	4.581%	$167.6224	$167.62	$167.60	$167.60
Purchase #4	$134.80	3.587%	$139.6353	$139.64	$139.65	$139.60
Purchase #5	$89.52	5.859%	$94.765	$94.77	$94.75	$94.80
Purchase #6	$176.57	13.415%	$200.2569	$200.26	$200.25	$200.30
Purchase #7	$22.42	10.243%	$24.7165	$24.72	$24.70	$24.70
7 purchase totals =	$984.40		$1,061.6857	$1,061.70	$1,061.60	$1,061.70