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	$211.85	13.864%	$241.2209	$241.22	$241.20	$241.20
Purchase #2	$140.38	3.388%	$145.1361	$145.14	$145.15	$145.10
Purchase #3	$249.86	5.367%	$263.27	$263.27	$263.25	$263.30
Purchase #4	$5.72	8.441%	$6.2028	$6.20	$6.20	$6.20
Purchase #5	$55.48	11.555%	$61.8907	$61.89	$61.90	$61.90
Purchase #6	$200.41	10.340%	$221.1324	$221.13	$221.15	$221.10
Purchase #7	$143.69	10.755%	$159.1439	$159.14	$159.15	$159.10
7 purchase totals =	$1,007.39		$1,097.9968	$1,097.99	$1,098.00	$1,097.90