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	$95.60	10.308%	$105.4544	$105.45	$105.45	$105.50
Purchase #2	$60.76	8.262%	$65.78	$65.78	$65.80	$65.80
Purchase #3	$185.44	4.721%	$194.1946	$194.19	$194.20	$194.20
Purchase #4	$205.33	3.168%	$211.8349	$211.83	$211.85	$211.80
Purchase #5	$94.28	4.436%	$98.4623	$98.46	$98.45	$98.50
Purchase #6	$183.36	6.731%	$195.702	$195.70	$195.70	$195.70
Purchase #7	$216.60	4.556%	$226.4683	$226.47	$226.45	$226.50
7 purchase totals =	$1,041.37		$1,097.8965	$1,097.88	$1,097.90	$1,098.00