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	$222.76	9.727%	$244.4279	$244.43	$244.45	$244.40
Purchase #2	$27.69	11.443%	$30.8586	$30.86	$30.85	$30.90
Purchase #3	$205.43	5.304%	$216.326	$216.33	$216.35	$216.30
Purchase #4	$164.33	8.374%	$178.091	$178.09	$178.10	$178.10
Purchase #5	$42.92	13.277%	$48.6185	$48.62	$48.60	$48.60
Purchase #6	$107.59	3.289%	$111.1286	$111.13	$111.15	$111.10
Purchase #7	$209.53	4.567%	$219.0992	$219.10	$219.10	$219.10
7 purchase totals =	$980.25		$1,048.5498	$1,048.56	$1,048.60	$1,048.50