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	$83.58	13.727%	$95.053	$95.05	$95.05	$95.10
Purchase #2	$225.39	13.405%	$255.6035	$255.60	$255.60	$255.60
Purchase #3	$19.78	10.528%	$21.8624	$21.86	$21.85	$21.90
Purchase #4	$69.27	12.198%	$77.7196	$77.72	$77.70	$77.70
Purchase #5	$156.72	13.217%	$177.4337	$177.43	$177.45	$177.40
Purchase #6	$183.84	13.819%	$209.2448	$209.24	$209.25	$209.20
Purchase #7	$178.91	3.816%	$185.7372	$185.74	$185.75	$185.70
7 purchase totals =	$917.49		$1,022.6542	$1,022.64	$1,022.65	$1,022.60