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	$69.48	3.533%	$71.9347	$71.93	$71.95	$71.90
Purchase #2	$8.40	5.170%	$8.8343	$8.83	$8.85	$8.80
Purchase #3	$94.88	11.406%	$105.702	$105.70	$105.70	$105.70
Purchase #4	$80.39	3.857%	$83.4906	$83.49	$83.50	$83.50
Purchase #5	$36.32	6.709%	$38.7567	$38.76	$38.75	$38.80
Purchase #6	$43.81	10.623%	$48.4639	$48.46	$48.45	$48.50
Purchase #7	$11.44	9.229%	$12.4958	$12.50	$12.50	$12.50
7 purchase totals =	$344.72		$369.6780	$369.67	$369.70	$369.70