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	$200.89	7.526%	$216.009	$216.01	$216.00	$216.00
Purchase #2	$73.26	12.738%	$82.5919	$82.59	$82.60	$82.60
Purchase #3	$173.36	9.858%	$190.4498	$190.45	$190.45	$190.40
Purchase #4	$84.78	13.834%	$96.5085	$96.51	$96.50	$96.50
Purchase #5	$56.32	10.243%	$62.0889	$62.09	$62.10	$62.10
Purchase #6	$232.25	6.317%	$246.9212	$246.92	$246.90	$246.90
Purchase #7	$247.75	6.339%	$263.4549	$263.45	$263.45	$263.50
7 purchase totals =	$1,068.61		$1,158.0242	$1,158.02	$1,158.00	$1,158.00