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	$198.26	8.437%	$214.9872	$214.99	$215.00	$215.00
Purchase #2	$14.68	7.384%	$15.764	$15.76	$15.75	$15.80
Purchase #3	$241.52	11.477%	$269.2393	$269.24	$269.25	$269.20
Purchase #4	$226.50	12.865%	$255.6392	$255.64	$255.65	$255.60
Purchase #5	$78.89	8.817%	$85.8457	$85.85	$85.85	$85.80
Purchase #6	$139.66	10.161%	$153.8509	$153.85	$153.85	$153.90
Purchase #7	$189.63	5.841%	$200.7063	$200.71	$200.70	$200.70
7 purchase totals =	$1,089.14		$1,196.0326	$1,196.04	$1,196.05	$1,196.00