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	$87.59	9.537%	$95.9435	$95.94	$95.95	$95.90
Purchase #2	$110.97	11.812%	$124.0778	$124.08	$124.10	$124.10
Purchase #3	$139.65	7.674%	$150.3667	$150.37	$150.35	$150.40
Purchase #4	$172.87	10.371%	$190.7983	$190.80	$190.80	$190.80
Purchase #5	$174.55	10.333%	$192.5863	$192.59	$192.60	$192.60
Purchase #6	$152.56	10.551%	$168.6566	$168.66	$168.65	$168.70
Purchase #7	$125.36	5.108%	$131.7634	$131.76	$131.75	$131.80
7 purchase totals =	$963.55		$1,054.1926	$1,054.20	$1,054.20	$1,054.30