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	$89.59	6.818%	$95.6982	$95.70	$95.70	$95.70
Purchase #2	$12.48	7.741%	$13.4461	$13.45	$13.45	$13.40
Purchase #3	$48.86	4.679%	$51.1462	$51.15	$51.15	$51.10
Purchase #4	$189.41	8.602%	$205.703	$205.70	$205.70	$205.70
Purchase #5	$246.98	7.665%	$265.911	$265.91	$265.90	$265.90
Purchase #6	$198.71	13.439%	$225.4146	$225.41	$225.40	$225.40
Purchase #7	$185.42	3.706%	$192.2917	$192.29	$192.30	$192.30
7 purchase totals =	$971.45		$1,049.6108	$1,049.61	$1,049.60	$1,049.50