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	$59.25	10.241%	$65.3178	$65.32	$65.30	$65.30
Purchase #2	$59.71	9.628%	$65.4589	$65.46	$65.45	$65.50
Purchase #3	$11.89	7.413%	$12.7714	$12.77	$12.75	$12.80
Purchase #4	$127.30	12.814%	$143.6122	$143.61	$143.60	$143.60
Purchase #5	$188.38	6.394%	$200.425	$200.43	$200.45	$200.40
Purchase #6	$201.29	6.858%	$215.0945	$215.09	$215.10	$215.10
Purchase #7	$231.32	13.729%	$263.0779	$263.08	$263.10	$263.10
7 purchase totals =	$879.14		$965.7577	$965.76	$965.75	$965.80