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	$219.81	11.282%	$244.609	$244.61	$244.60	$244.60
Purchase #2	$219.40	11.329%	$244.2558	$244.26	$244.25	$244.30
Purchase #3	$207.82	11.587%	$231.9001	$231.90	$231.90	$231.90
Purchase #4	$105.50	5.832%	$111.6528	$111.65	$111.65	$111.70
Purchase #5	$63.34	6.408%	$67.3988	$67.40	$67.40	$67.40
Purchase #6	$120.48	4.789%	$126.2498	$126.25	$126.25	$126.20
Purchase #7	$110.63	6.831%	$118.1871	$118.19	$118.20	$118.20
7 purchase totals =	$1,046.98		$1,144.2534	$1,144.26	$1,144.25	$1,144.30