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	$116.65	7.406%	$125.2891	$125.29	$125.30	$125.30
Purchase #2	$145.54	4.167%	$151.6047	$151.60	$151.60	$151.60
Purchase #3	$239.83	6.606%	$255.6732	$255.67	$255.65	$255.70
Purchase #4	$117.51	4.596%	$122.9108	$122.91	$122.90	$122.90
Purchase #5	$213.85	11.675%	$238.817	$238.82	$238.80	$238.80
Purchase #6	$10.76	8.832%	$11.7103	$11.71	$11.70	$11.70
Purchase #7	$121.68	4.592%	$127.2675	$127.27	$127.25	$127.30
7 purchase totals =	$965.82		$1,033.2726	$1,033.27	$1,033.20	$1,033.30