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	$176.46	9.840%	$193.8237	$193.82	$193.80	$193.80
Purchase #2	$77.58	5.250%	$81.653	$81.65	$81.65	$81.70
Purchase #3	$231.76	7.133%	$248.2914	$248.29	$248.30	$248.30
Purchase #4	$70.40	10.838%	$78.03	$78.03	$78.05	$78.00
Purchase #5	$185.64	3.163%	$191.5118	$191.51	$191.50	$191.50
Purchase #6	$155.92	5.233%	$164.0793	$164.08	$164.10	$164.10
Purchase #7	$83.67	8.244%	$90.5678	$90.57	$90.55	$90.60
7 purchase totals =	$981.43		$1,047.9570	$1,047.95	$1,047.95	$1,048.00