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	$195.72	3.846%	$203.2474	$203.25	$203.25	$203.20
Purchase #2	$10.30	10.842%	$11.4167	$11.42	$11.40	$11.40
Purchase #3	$143.28	11.403%	$159.6182	$159.62	$159.60	$159.60
Purchase #4	$125.98	13.873%	$143.4572	$143.46	$143.45	$143.50
Purchase #5	$170.35	9.102%	$185.8553	$185.86	$185.85	$185.90
Purchase #6	$71.81	7.440%	$77.1527	$77.15	$77.15	$77.20
Purchase #7	$243.96	11.812%	$272.7766	$272.78	$272.80	$272.80
7 purchase totals =	$961.40		$1,053.5241	$1,053.54	$1,053.50	$1,053.60