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	$181.56	7.717%	$195.571	$195.57	$195.55	$195.60
Purchase #2	$208.36	7.142%	$223.2411	$223.24	$223.25	$223.20
Purchase #3	$155.75	12.551%	$175.2982	$175.30	$175.30	$175.30
Purchase #4	$148.57	13.553%	$168.7057	$168.71	$168.70	$168.70
Purchase #5	$196.87	9.143%	$214.8698	$214.87	$214.85	$214.90
Purchase #6	$58.59	3.272%	$60.5071	$60.51	$60.50	$60.50
Purchase #7	$73.99	6.405%	$78.7291	$78.73	$78.75	$78.70
7 purchase totals =	$1,023.69		$1,116.9220	$1,116.93	$1,116.90	$1,116.90