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	$193.52	4.760%	$202.7316	$202.73	$202.75	$202.70
Purchase #2	$71.64	6.816%	$76.523	$76.52	$76.50	$76.50
Purchase #3	$112.93	13.120%	$127.7464	$127.75	$127.75	$127.70
Purchase #4	$214.71	12.479%	$241.5037	$241.50	$241.50	$241.50
Purchase #5	$209.88	11.184%	$233.353	$233.35	$233.35	$233.40
Purchase #6	$33.95	10.563%	$37.5361	$37.54	$37.55	$37.50
Purchase #7	$179.66	5.693%	$189.888	$189.89	$189.90	$189.90
7 purchase totals =	$1,016.29		$1,109.2818	$1,109.28	$1,109.30	$1,109.20