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	$174.62	11.235%	$194.2386	$194.24	$194.25	$194.20
Purchase #2	$132.54	11.126%	$147.2864	$147.29	$147.30	$147.30
Purchase #3	$229.31	3.462%	$237.2487	$237.25	$237.25	$237.20
Purchase #4	$225.37	7.146%	$241.4749	$241.47	$241.45	$241.50
Purchase #5	$69.33	3.597%	$71.8238	$71.82	$71.80	$71.80
Purchase #6	$43.98	12.386%	$49.4274	$49.43	$49.45	$49.40
Purchase #7	$231.65	10.170%	$255.2088	$255.21	$255.20	$255.20
7 purchase totals =	$1,106.80		$1,196.7086	$1,196.71	$1,196.70	$1,196.60