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	$113.83	10.197%	$125.4372	$125.44	$125.45	$125.40
Purchase #2	$177.57	7.586%	$191.0405	$191.04	$191.05	$191.00
Purchase #3	$176.46	11.278%	$196.3612	$196.36	$196.35	$196.40
Purchase #4	$176.82	7.672%	$190.3856	$190.39	$190.40	$190.40
Purchase #5	$182.79	7.403%	$196.3219	$196.32	$196.30	$196.30
Purchase #6	$105.44	13.257%	$119.4182	$119.42	$119.40	$119.40
Purchase #7	$24.79	13.325%	$28.0933	$28.09	$28.10	$28.10
7 purchase totals =	$957.70		$1,047.0579	$1,047.06	$1,047.05	$1,047.00