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	$59.53	5.613%	$62.8714	$62.87	$62.85	$62.90
Purchase #2	$192.34	4.371%	$200.7472	$200.75	$200.75	$200.70
Purchase #3	$46.61	7.788%	$50.24	$50.24	$50.25	$50.20
Purchase #4	$8.89	13.832%	$10.1197	$10.12	$10.10	$10.10
Purchase #5	$117.38	12.230%	$131.7356	$131.74	$131.75	$131.70
Purchase #6	$157.45	6.863%	$168.2558	$168.26	$168.25	$168.30
Purchase #7	$111.83	10.789%	$123.8953	$123.90	$123.90	$123.90
7 purchase totals =	$694.03		$747.8650	$747.88	$747.85	$747.80