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	$195.78	11.770%	$218.8233	$218.82	$218.80	$218.80
Purchase #2	$13.52	5.453%	$14.2572	$14.26	$14.25	$14.30
Purchase #3	$10.86	13.767%	$12.3551	$12.36	$12.35	$12.40
Purchase #4	$64.43	4.358%	$67.2379	$67.24	$67.25	$67.20
Purchase #5	$39.68	9.269%	$43.3579	$43.36	$43.35	$43.40
Purchase #6	$56.47	10.440%	$62.3655	$62.37	$62.35	$62.40
Purchase #7	$136.63	5.108%	$143.6091	$143.61	$143.60	$143.60
7 purchase totals =	$517.37		$562.0060	$562.02	$561.95	$562.10