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	$141.60	9.185%	$154.606	$154.61	$154.60	$154.60
Purchase #2	$54.87	3.116%	$56.5797	$56.58	$56.60	$56.60
Purchase #3	$90.59	3.800%	$94.0324	$94.03	$94.05	$94.00
Purchase #4	$233.39	3.873%	$242.4292	$242.43	$242.45	$242.40
Purchase #5	$168.28	4.212%	$175.368	$175.37	$175.35	$175.40
Purchase #6	$168.42	3.163%	$173.7471	$173.75	$173.75	$173.70
Purchase #7	$190.67	4.855%	$199.927	$199.93	$199.95	$199.90
7 purchase totals =	$1,047.82		$1,096.6894	$1,096.70	$1,096.75	$1,096.60