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	$228.47	5.510%	$241.0587	$241.06	$241.05	$241.10
Purchase #2	$9.60	6.464%	$10.2205	$10.22	$10.20	$10.20
Purchase #3	$231.86	12.448%	$260.7219	$260.72	$260.70	$260.70
Purchase #4	$85.67	11.488%	$95.5118	$95.51	$95.50	$95.50
Purchase #5	$235.37	8.423%	$255.1952	$255.20	$255.20	$255.20
Purchase #6	$99.90	5.573%	$105.4674	$105.47	$105.45	$105.50
Purchase #7	$59.52	10.822%	$65.9613	$65.96	$65.95	$66.00
7 purchase totals =	$950.39		$1,034.1368	$1,034.14	$1,034.05	$1,034.20