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	$161.89	3.751%	$167.9625	$167.96	$167.95	$168.00
Purchase #2	$185.67	5.254%	$195.4251	$195.43	$195.45	$195.40
Purchase #3	$216.59	4.314%	$225.9337	$225.93	$225.95	$225.90
Purchase #4	$63.55	12.692%	$71.6158	$71.62	$71.60	$71.60
Purchase #5	$113.96	11.378%	$126.9264	$126.93	$126.95	$126.90
Purchase #6	$143.87	3.839%	$149.3932	$149.39	$149.40	$149.40
Purchase #7	$196.53	7.155%	$210.5917	$210.59	$210.60	$210.60
7 purchase totals =	$1,082.06		$1,147.8484	$1,147.85	$1,147.90	$1,147.80