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	$194.51	10.539%	$215.0094	$215.01	$215.00	$215.00
Purchase #2	$168.51	12.525%	$189.6159	$189.62	$189.60	$189.60
Purchase #3	$77.37	12.551%	$87.0807	$87.08	$87.10	$87.10
Purchase #4	$73.97	9.757%	$81.1873	$81.19	$81.20	$81.20
Purchase #5	$52.37	3.462%	$54.183	$54.18	$54.20	$54.20
Purchase #6	$172.83	6.658%	$184.337	$184.34	$184.35	$184.30
Purchase #7	$175.81	11.796%	$196.5485	$196.55	$196.55	$196.50
7 purchase totals =	$915.37		$1,007.9618	$1,007.97	$1,008.00	$1,007.90