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	$212.41	10.379%	$234.456	$234.46	$234.45	$234.50
Purchase #2	$55.48	8.641%	$60.274	$60.27	$60.25	$60.30
Purchase #3	$227.33	6.511%	$242.1315	$242.13	$242.15	$242.10
Purchase #4	$168.77	4.269%	$175.9748	$175.97	$175.95	$176.00
Purchase #5	$144.89	6.291%	$154.005	$154.01	$154.00	$154.00
Purchase #6	$206.65	8.322%	$223.8474	$223.85	$223.85	$223.80
Purchase #7	$9.51	8.114%	$10.2816	$10.28	$10.30	$10.30
7 purchase totals =	$1,025.04		$1,100.9703	$1,100.97	$1,100.95	$1,101.00