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	$204.33	9.103%	$222.9302	$222.93	$222.95	$222.90
Purchase #2	$139.43	6.629%	$148.6728	$148.67	$148.65	$148.70
Purchase #3	$238.80	3.658%	$247.5353	$247.54	$247.55	$247.50
Purchase #4	$10.87	4.605%	$11.3706	$11.37	$11.35	$11.40
Purchase #5	$63.77	11.779%	$71.2815	$71.28	$71.30	$71.30
Purchase #6	$100.60	12.720%	$113.3963	$113.40	$113.40	$113.40
Purchase #7	$187.81	11.678%	$209.7425	$209.74	$209.75	$209.70
7 purchase totals =	$945.61		$1,024.9292	$1,024.93	$1,024.95	$1,024.90