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	$23.28	11.387%	$25.9309	$25.93	$25.95	$25.90
Purchase #2	$6.52	5.347%	$6.8686	$6.87	$6.85	$6.90
Purchase #3	$101.95	11.103%	$113.2695	$113.27	$113.25	$113.30
Purchase #4	$230.53	6.325%	$245.111	$245.11	$245.10	$245.10
Purchase #5	$17.67	4.531%	$18.4706	$18.47	$18.45	$18.50
Purchase #6	$38.84	9.602%	$42.5694	$42.57	$42.55	$42.60
Purchase #7	$12.77	4.238%	$13.3112	$13.31	$13.30	$13.30
7 purchase totals =	$431.56		$465.5312	$465.53	$465.45	$465.60