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	$219.57	11.129%	$244.0059	$244.01	$244.00	$244.00
Purchase #2	$150.81	7.464%	$162.0665	$162.07	$162.05	$162.10
Purchase #3	$60.64	5.164%	$63.7714	$63.77	$63.75	$63.80
Purchase #4	$80.86	6.244%	$85.9089	$85.91	$85.90	$85.90
Purchase #5	$114.72	11.118%	$127.4746	$127.47	$127.45	$127.50
Purchase #6	$27.58	11.465%	$30.742	$30.74	$30.75	$30.70
Purchase #7	$154.39	11.424%	$172.0275	$172.03	$172.05	$172.00
7 purchase totals =	$808.57		$885.9968	$886.00	$885.95	$886.00