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	$193.67	3.484%	$200.4175	$200.42	$200.40	$200.40
Purchase #2	$214.38	8.727%	$233.0889	$233.09	$233.10	$233.10
Purchase #3	$57.48	13.130%	$65.0271	$65.03	$65.05	$65.00
Purchase #4	$45.41	13.494%	$51.5376	$51.54	$51.55	$51.50
Purchase #5	$242.62	11.561%	$270.6693	$270.67	$270.65	$270.70
Purchase #6	$218.65	4.443%	$228.3646	$228.36	$228.35	$228.40
Purchase #7	$42.60	7.713%	$45.8857	$45.89	$45.90	$45.90
7 purchase totals =	$1,014.81		$1,094.9907	$1,095.00	$1,095.00	$1,095.00