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	$191.65	11.730%	$214.1305	$214.13	$214.15	$214.10
Purchase #2	$27.41	3.103%	$28.2605	$28.26	$28.25	$28.30
Purchase #3	$5.42	3.206%	$5.5938	$5.59	$5.60	$5.60
Purchase #4	$221.56	5.585%	$233.9341	$233.93	$233.95	$233.90
Purchase #5	$6.66	12.187%	$7.4717	$7.47	$7.45	$7.50
Purchase #6	$55.99	6.862%	$59.832	$59.83	$59.85	$59.80
Purchase #7	$209.98	11.380%	$233.8757	$233.88	$233.90	$233.90
7 purchase totals =	$718.67		$783.0983	$783.09	$783.15	$783.10