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	$175.72	13.796%	$199.9623	$199.96	$199.95	$200.00
Purchase #2	$139.32	6.667%	$148.6085	$148.61	$148.60	$148.60
Purchase #3	$54.94	3.485%	$56.8547	$56.85	$56.85	$56.90
Purchase #4	$216.73	5.241%	$228.0888	$228.09	$228.10	$228.10
Purchase #5	$161.82	10.675%	$179.0943	$179.09	$179.10	$179.10
Purchase #6	$195.76	8.537%	$212.472	$212.47	$212.45	$212.50
Purchase #7	$79.95	13.746%	$90.9399	$90.94	$90.95	$90.90
7 purchase totals =	$1,024.24		$1,116.0205	$1,116.01	$1,116.00	$1,116.10