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	$143.66	7.146%	$153.9259	$153.93	$153.95	$153.90
Purchase #2	$85.89	8.326%	$93.0412	$93.04	$93.05	$93.00
Purchase #3	$129.39	9.258%	$141.3689	$141.37	$141.35	$141.40
Purchase #4	$216.56	5.163%	$227.741	$227.74	$227.75	$227.70
Purchase #5	$10.91	6.134%	$11.5792	$11.58	$11.60	$11.60
Purchase #6	$179.97	5.778%	$190.3687	$190.37	$190.35	$190.40
Purchase #7	$189.65	3.661%	$196.5931	$196.59	$196.60	$196.60
7 purchase totals =	$956.03		$1,014.6180	$1,014.62	$1,014.65	$1,014.60