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	$176.38	11.398%	$196.4838	$196.48	$196.50	$196.50
Purchase #2	$198.40	5.853%	$210.0124	$210.01	$210.00	$210.00
Purchase #3	$204.62	5.197%	$215.2541	$215.25	$215.25	$215.30
Purchase #4	$219.57	6.856%	$234.6237	$234.62	$234.60	$234.60
Purchase #5	$188.45	3.210%	$194.4992	$194.50	$194.50	$194.50
Purchase #6	$114.36	11.489%	$127.4988	$127.50	$127.50	$127.50
Purchase #7	$180.92	9.768%	$198.5923	$198.59	$198.60	$198.60
7 purchase totals =	$1,282.70		$1,376.9643	$1,376.95	$1,376.95	$1,377.00