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	$87.65	8.435%	$95.0433	$95.04	$95.05	$95.00
Purchase #2	$155.56	8.558%	$168.8728	$168.87	$168.85	$168.90
Purchase #3	$238.62	7.138%	$255.6527	$255.65	$255.65	$255.70
Purchase #4	$237.83	3.448%	$246.0304	$246.03	$246.05	$246.00
Purchase #5	$137.61	11.393%	$153.2879	$153.29	$153.30	$153.30
Purchase #6	$165.59	11.342%	$184.3712	$184.37	$184.35	$184.40
Purchase #7	$87.41	6.271%	$92.8915	$92.89	$92.90	$92.90
7 purchase totals =	$1,110.27		$1,196.1498	$1,196.14	$1,196.15	$1,196.20