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	$193.62	10.326%	$213.6132	$213.61	$213.60	$213.60
Purchase #2	$48.43	8.491%	$52.5422	$52.54	$52.55	$52.50
Purchase #3	$99.55	5.318%	$104.8441	$104.84	$104.85	$104.80
Purchase #4	$21.38	10.297%	$23.5815	$23.58	$23.60	$23.60
Purchase #5	$170.46	10.668%	$188.6447	$188.64	$188.65	$188.60
Purchase #6	$230.38	10.258%	$254.0124	$254.01	$254.00	$254.00
Purchase #7	$169.59	5.704%	$179.2634	$179.26	$179.25	$179.30
7 purchase totals =	$933.41		$1,016.5015	$1,016.48	$1,016.50	$1,016.40