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	$213.65	11.443%	$238.098	$238.10	$238.10	$238.10
Purchase #2	$69.25	4.203%	$72.1606	$72.16	$72.15	$72.20
Purchase #3	$244.48	13.834%	$278.3014	$278.30	$278.30	$278.30
Purchase #4	$51.80	12.221%	$58.1305	$58.13	$58.15	$58.10
Purchase #5	$195.85	3.441%	$202.5892	$202.59	$202.60	$202.60
Purchase #6	$122.98	11.275%	$136.846	$136.85	$136.85	$136.80
Purchase #7	$154.72	8.240%	$167.4689	$167.47	$167.45	$167.50
7 purchase totals =	$1,052.73		$1,153.5946	$1,153.60	$1,153.60	$1,153.60