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	$145.89	4.491%	$152.4419	$152.44	$152.45	$152.40
Purchase #2	$239.52	3.743%	$248.4852	$248.49	$248.50	$248.50
Purchase #3	$193.34	12.657%	$217.811	$217.81	$217.80	$217.80
Purchase #4	$54.74	5.232%	$57.604	$57.60	$57.60	$57.60
Purchase #5	$40.70	4.388%	$42.4859	$42.49	$42.50	$42.50
Purchase #6	$68.92	5.612%	$72.7878	$72.79	$72.80	$72.80
Purchase #7	$209.60	11.778%	$234.2867	$234.29	$234.30	$234.30
7 purchase totals =	$952.71		$1,025.9025	$1,025.91	$1,025.95	$1,025.90