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	$168.41	3.325%	$174.0096	$174.01	$174.00	$174.00
Purchase #2	$17.43	12.668%	$19.638	$19.64	$19.65	$19.60
Purchase #3	$89.30	10.397%	$98.5845	$98.58	$98.60	$98.60
Purchase #4	$247.93	6.330%	$263.624	$263.62	$263.60	$263.60
Purchase #5	$231.63	8.857%	$252.1455	$252.15	$252.15	$252.10
Purchase #6	$185.78	12.116%	$208.2891	$208.29	$208.30	$208.30
Purchase #7	$106.29	4.651%	$111.2335	$111.23	$111.25	$111.20
7 purchase totals =	$1,046.77		$1,127.5242	$1,127.52	$1,127.55	$1,127.40