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	$117.76	7.698%	$126.8252	$126.83	$126.85	$126.80
Purchase #2	$172.71	9.735%	$189.5233	$189.52	$189.50	$189.50
Purchase #3	$54.81	4.755%	$57.4162	$57.42	$57.40	$57.40
Purchase #4	$205.96	7.702%	$221.823	$221.82	$221.80	$221.80
Purchase #5	$68.38	3.427%	$70.7234	$70.72	$70.70	$70.70
Purchase #6	$177.93	5.115%	$187.0311	$187.03	$187.05	$187.00
Purchase #7	$144.52	12.763%	$162.9651	$162.97	$162.95	$163.00
7 purchase totals =	$942.07		$1,016.3073	$1,016.31	$1,016.25	$1,016.20