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	$182.50	4.686%	$191.052	$191.05	$191.05	$191.10
Purchase #2	$54.59	4.423%	$57.0045	$57.00	$57.00	$57.00
Purchase #3	$100.43	11.698%	$112.1783	$112.18	$112.20	$112.20
Purchase #4	$155.32	11.590%	$173.3216	$173.32	$173.30	$173.30
Purchase #5	$235.32	8.738%	$255.8823	$255.88	$255.90	$255.90
Purchase #6	$152.84	5.189%	$160.7709	$160.77	$160.75	$160.80
Purchase #7	$57.99	5.651%	$61.267	$61.27	$61.25	$61.30
7 purchase totals =	$938.99		$1,011.4766	$1,011.47	$1,011.45	$1,011.60