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	$182.56	7.377%	$196.0275	$196.03	$196.05	$196.00
Purchase #2	$78.95	4.665%	$82.633	$82.63	$82.65	$82.60
Purchase #3	$111.49	13.795%	$126.87	$126.87	$126.85	$126.90
Purchase #4	$245.87	6.628%	$262.1663	$262.17	$262.15	$262.20
Purchase #5	$224.47	11.650%	$250.6208	$250.62	$250.60	$250.60
Purchase #6	$126.82	8.203%	$137.223	$137.22	$137.20	$137.20
Purchase #7	$69.66	4.540%	$72.8226	$72.82	$72.80	$72.80
7 purchase totals =	$1,039.82		$1,128.3632	$1,128.36	$1,128.30	$1,128.30