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	$181.42	8.128%	$196.1658	$196.17	$196.15	$196.20
Purchase #2	$111.45	5.478%	$117.5552	$117.56	$117.55	$117.60
Purchase #3	$47.93	4.121%	$49.9052	$49.91	$49.90	$49.90
Purchase #4	$17.80	3.420%	$18.4088	$18.41	$18.40	$18.40
Purchase #5	$115.93	12.579%	$130.5128	$130.51	$130.50	$130.50
Purchase #6	$43.35	5.211%	$45.609	$45.61	$45.60	$45.60
Purchase #7	$136.78	5.605%	$144.4465	$144.45	$144.45	$144.40
7 purchase totals =	$654.66		$702.6033	$702.62	$702.55	$702.60