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	$142.71	6.523%	$152.019	$152.02	$152.00	$152.00
Purchase #2	$11.38	11.150%	$12.6489	$12.65	$12.65	$12.60
Purchase #3	$7.50	3.647%	$7.7735	$7.77	$7.75	$7.80
Purchase #4	$203.47	11.605%	$227.0827	$227.08	$227.10	$227.10
Purchase #5	$57.81	10.776%	$64.0396	$64.04	$64.05	$64.00
Purchase #6	$146.93	5.862%	$155.543	$155.54	$155.55	$155.50
Purchase #7	$106.72	5.403%	$112.4861	$112.49	$112.50	$112.50
7 purchase totals =	$676.52		$731.5928	$731.59	$731.60	$731.50