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	$190.41	11.468%	$212.2462	$212.25	$212.25	$212.20
Purchase #2	$165.97	10.681%	$183.6973	$183.70	$183.70	$183.70
Purchase #3	$78.66	4.727%	$82.3783	$82.38	$82.40	$82.40
Purchase #4	$90.77	10.315%	$100.1329	$100.13	$100.15	$100.10
Purchase #5	$104.98	6.560%	$111.8667	$111.87	$111.85	$111.90
Purchase #6	$139.95	12.628%	$157.6229	$157.62	$157.60	$157.60
Purchase #7	$192.75	4.245%	$200.9322	$200.93	$200.95	$200.90
7 purchase totals =	$963.49		$1,048.8765	$1,048.88	$1,048.90	$1,048.80