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	$168.95	3.669%	$175.1488	$175.15	$175.15	$175.10
Purchase #2	$64.76	11.572%	$72.254	$72.25	$72.25	$72.30
Purchase #3	$154.62	8.664%	$168.0163	$168.02	$168.00	$168.00
Purchase #4	$38.47	12.848%	$43.4126	$43.41	$43.40	$43.40
Purchase #5	$94.25	6.511%	$100.3866	$100.39	$100.40	$100.40
Purchase #6	$183.56	6.557%	$195.596	$195.60	$195.60	$195.60
Purchase #7	$244.56	7.303%	$262.4202	$262.42	$262.40	$262.40
7 purchase totals =	$949.17		$1,017.2345	$1,017.24	$1,017.20	$1,017.20