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	$184.29	5.414%	$194.2675	$194.27	$194.25	$194.30
Purchase #2	$95.74	5.405%	$100.9147	$100.91	$100.90	$100.90
Purchase #3	$162.72	4.838%	$170.5924	$170.59	$170.60	$170.60
Purchase #4	$163.37	6.248%	$173.5774	$173.58	$173.60	$173.60
Purchase #5	$157.71	6.777%	$168.398	$168.40	$168.40	$168.40
Purchase #6	$147.98	5.198%	$155.672	$155.67	$155.65	$155.70
Purchase #7	$47.93	12.832%	$54.0804	$54.08	$54.10	$54.10
7 purchase totals =	$959.74		$1,017.5024	$1,017.50	$1,017.50	$1,017.60