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	$176.93	11.260%	$196.8523	$196.85	$196.85	$196.90
Purchase #2	$10.98	5.507%	$11.5847	$11.58	$11.60	$11.60
Purchase #3	$221.31	10.625%	$244.8242	$244.82	$244.80	$244.80
Purchase #4	$138.77	10.434%	$153.2493	$153.25	$153.25	$153.20
Purchase #5	$166.57	9.151%	$181.8128	$181.81	$181.80	$181.80
Purchase #6	$42.81	7.792%	$46.1458	$46.15	$46.15	$46.10
Purchase #7	$200.57	9.706%	$220.0373	$220.04	$220.05	$220.00
7 purchase totals =	$957.94		$1,054.5064	$1,054.50	$1,054.50	$1,054.40