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	$54.61	13.819%	$62.1566	$62.16	$62.15	$62.20
Purchase #2	$89.30	3.763%	$92.6604	$92.66	$92.65	$92.70
Purchase #3	$11.77	9.469%	$12.8845	$12.88	$12.90	$12.90
Purchase #4	$41.86	8.232%	$45.3059	$45.31	$45.30	$45.30
Purchase #5	$247.32	3.341%	$255.583	$255.58	$255.60	$255.60
Purchase #6	$69.61	12.233%	$78.1254	$78.13	$78.15	$78.10
Purchase #7	$143.83	8.181%	$155.5967	$155.60	$155.60	$155.60
7 purchase totals =	$658.30		$702.3125	$702.32	$702.35	$702.40