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	$97.81	4.137%	$101.8564	$101.86	$101.85	$101.90
Purchase #2	$10.52	10.156%	$11.5884	$11.59	$11.60	$11.60
Purchase #3	$84.56	12.746%	$95.338	$95.34	$95.35	$95.30
Purchase #4	$19.52	9.322%	$21.3397	$21.34	$21.35	$21.30
Purchase #5	$237.42	11.845%	$265.5424	$265.54	$265.55	$265.50
Purchase #6	$48.75	3.604%	$50.507	$50.51	$50.50	$50.50
Purchase #7	$170.85	9.762%	$187.5284	$187.53	$187.55	$187.50
7 purchase totals =	$669.43		$733.7003	$733.71	$733.75	$733.60