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	$176.65	11.361%	$196.7192	$196.72	$196.70	$196.70
Purchase #2	$219.67	12.291%	$246.6696	$246.67	$246.65	$246.70
Purchase #3	$162.70	5.816%	$172.1626	$172.16	$172.15	$172.20
Purchase #4	$148.68	11.389%	$165.6132	$165.61	$165.60	$165.60
Purchase #5	$214.45	3.834%	$222.672	$222.67	$222.65	$222.70
Purchase #6	$166.71	3.224%	$172.0847	$172.08	$172.10	$172.10
Purchase #7	$202.61	11.867%	$226.6537	$226.65	$226.65	$226.70
7 purchase totals =	$1,291.47		$1,402.5750	$1,402.56	$1,402.50	$1,402.70