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	$196.68	8.535%	$213.4666	$213.47	$213.45	$213.50
Purchase #2	$164.33	13.591%	$186.6641	$186.66	$186.65	$186.70
Purchase #3	$187.35	6.313%	$199.1774	$199.18	$199.20	$199.20
Purchase #4	$45.57	11.585%	$50.8493	$50.85	$50.85	$50.80
Purchase #5	$152.90	13.577%	$173.6592	$173.66	$173.65	$173.70
Purchase #6	$175.70	10.142%	$193.5195	$193.52	$193.50	$193.50
Purchase #7	$119.59	6.346%	$127.1792	$127.18	$127.20	$127.20
7 purchase totals =	$1,042.12		$1,144.5153	$1,144.52	$1,144.50	$1,144.60