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	$237.25	10.546%	$262.2704	$262.27	$262.25	$262.30
Purchase #2	$21.94	3.537%	$22.716	$22.72	$22.70	$22.70
Purchase #3	$229.95	3.821%	$238.7364	$238.74	$238.75	$238.70
Purchase #4	$89.35	11.730%	$99.8308	$99.83	$99.85	$99.80
Purchase #5	$183.69	3.583%	$190.2716	$190.27	$190.25	$190.30
Purchase #6	$96.46	7.627%	$103.817	$103.82	$103.80	$103.80
Purchase #7	$88.50	12.639%	$99.6855	$99.69	$99.70	$99.70
7 purchase totals =	$947.14		$1,017.3277	$1,017.34	$1,017.30	$1,017.30