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	$186.87	9.689%	$204.9758	$204.98	$205.00	$205.00
Purchase #2	$74.97	4.710%	$78.5011	$78.50	$78.50	$78.50
Purchase #3	$46.37	13.105%	$52.4468	$52.45	$52.45	$52.40
Purchase #4	$196.67	9.115%	$214.5965	$214.60	$214.60	$214.60
Purchase #5	$126.53	3.435%	$130.8763	$130.88	$130.90	$130.90
Purchase #6	$216.46	3.197%	$223.3802	$223.38	$223.40	$223.40
Purchase #7	$100.59	11.332%	$111.9889	$111.99	$112.00	$112.00
7 purchase totals =	$948.46		$1,016.7656	$1,016.78	$1,016.85	$1,016.80