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	$177.60	10.401%	$196.0722	$196.07	$196.05	$196.10
Purchase #2	$21.96	4.465%	$22.9405	$22.94	$22.95	$22.90
Purchase #3	$53.53	13.334%	$60.6677	$60.67	$60.65	$60.70
Purchase #4	$166.87	7.643%	$179.6239	$179.62	$179.60	$179.60
Purchase #5	$196.79	8.660%	$213.832	$213.83	$213.85	$213.80
Purchase #6	$237.59	3.332%	$245.5065	$245.51	$245.50	$245.50
Purchase #7	$229.50	10.742%	$254.1529	$254.15	$254.15	$254.20
7 purchase totals =	$1,083.84		$1,172.7957	$1,172.79	$1,172.75	$1,172.80