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	$69.67	3.409%	$72.0451	$72.05	$72.05	$72.00
Purchase #2	$93.71	11.563%	$104.5457	$104.55	$104.55	$104.50
Purchase #3	$55.28	3.635%	$57.2894	$57.29	$57.30	$57.30
Purchase #4	$201.43	7.554%	$216.646	$216.65	$216.65	$216.60
Purchase #5	$157.47	13.217%	$178.2828	$178.28	$178.30	$178.30
Purchase #6	$209.55	11.461%	$233.5665	$233.57	$233.55	$233.60
Purchase #7	$141.68	7.178%	$151.8498	$151.85	$151.85	$151.80
7 purchase totals =	$928.79		$1,014.2253	$1,014.24	$1,014.25	$1,014.10