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	$119.32	6.739%	$127.361	$127.36	$127.35	$127.40
Purchase #2	$74.71	13.380%	$84.7062	$84.71	$84.70	$84.70
Purchase #3	$208.94	6.471%	$222.4605	$222.46	$222.45	$222.50
Purchase #4	$65.78	11.628%	$73.4289	$73.43	$73.45	$73.40
Purchase #5	$155.47	4.610%	$162.6372	$162.64	$162.65	$162.60
Purchase #6	$80.39	10.506%	$88.8358	$88.84	$88.85	$88.80
Purchase #7	$228.33	11.499%	$254.5857	$254.59	$254.60	$254.60
7 purchase totals =	$932.94		$1,014.0153	$1,014.03	$1,014.05	$1,014.00