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	$200.72	7.550%	$215.8744	$215.87	$215.85	$215.90
Purchase #2	$14.70	7.376%	$15.7843	$15.78	$15.80	$15.80
Purchase #3	$247.56	4.578%	$258.8933	$258.89	$258.90	$258.90
Purchase #4	$179.82	5.360%	$189.4584	$189.46	$189.45	$189.50
Purchase #5	$124.42	6.732%	$132.796	$132.80	$132.80	$132.80
Purchase #6	$163.43	6.866%	$174.6511	$174.65	$174.65	$174.70
Purchase #7	$222.27	8.174%	$240.4383	$240.44	$240.45	$240.40
7 purchase totals =	$1,152.92		$1,227.8958	$1,227.89	$1,227.90	$1,228.00