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	$212.26	13.601%	$241.1295	$241.13	$241.15	$241.10
Purchase #2	$162.81	3.854%	$169.0847	$169.08	$169.10	$169.10
Purchase #3	$10.80	3.158%	$11.1411	$11.14	$11.15	$11.10
Purchase #4	$60.80	6.232%	$64.5891	$64.59	$64.60	$64.60
Purchase #5	$224.80	3.684%	$233.0816	$233.08	$233.10	$233.10
Purchase #6	$114.55	11.449%	$127.6648	$127.66	$127.65	$127.70
Purchase #7	$227.79	13.412%	$258.3412	$258.34	$258.35	$258.30
7 purchase totals =	$1,013.81		$1,105.0320	$1,105.02	$1,105.10	$1,105.00