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	$213.26	3.569%	$220.8712	$220.87	$220.85	$220.90
Purchase #2	$65.27	6.623%	$69.5928	$69.59	$69.60	$69.60
Purchase #3	$39.99	12.186%	$44.8632	$44.86	$44.85	$44.90
Purchase #4	$98.65	6.567%	$105.1283	$105.13	$105.15	$105.10
Purchase #5	$190.54	3.110%	$196.4658	$196.47	$196.45	$196.50
Purchase #6	$164.91	13.471%	$187.125	$187.13	$187.15	$187.10
Purchase #7	$170.52	11.427%	$190.0053	$190.01	$190.00	$190.00
7 purchase totals =	$943.14		$1,014.0516	$1,014.06	$1,014.05	$1,014.10