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	$191.69	9.591%	$210.075	$210.08	$210.10	$210.10
Purchase #2	$5.60	9.858%	$6.152	$6.15	$6.15	$6.20
Purchase #3	$140.56	13.466%	$159.4878	$159.49	$159.50	$159.50
Purchase #4	$99.52	13.373%	$112.8288	$112.83	$112.85	$112.80
Purchase #5	$243.45	6.145%	$258.41	$258.41	$258.40	$258.40
Purchase #6	$17.56	7.864%	$18.9409	$18.94	$18.95	$18.90
Purchase #7	$227.38	9.138%	$248.158	$248.16	$248.15	$248.20
7 purchase totals =	$925.76		$1,014.0525	$1,014.06	$1,014.10	$1,014.10