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	$196.25	5.198%	$206.4511	$206.45	$206.45	$206.50
Purchase #2	$184.77	7.836%	$199.2486	$199.25	$199.25	$199.20
Purchase #3	$69.55	4.656%	$72.7882	$72.79	$72.80	$72.80
Purchase #4	$54.59	12.721%	$61.5344	$61.53	$61.55	$61.50
Purchase #5	$153.60	8.393%	$166.4916	$166.49	$166.50	$166.50
Purchase #6	$140.29	8.328%	$151.9734	$151.97	$151.95	$152.00
Purchase #7	$202.69	6.509%	$215.8831	$215.88	$215.90	$215.90
7 purchase totals =	$1,001.74		$1,074.3704	$1,074.36	$1,074.40	$1,074.40