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	$208.87	11.584%	$233.0655	$233.07	$233.05	$233.10
Purchase #2	$146.40	3.193%	$151.0746	$151.07	$151.05	$151.10
Purchase #3	$13.28	6.506%	$14.144	$14.14	$14.15	$14.10
Purchase #4	$197.98	11.691%	$221.1258	$221.13	$221.15	$221.10
Purchase #5	$172.85	8.367%	$187.3124	$187.31	$187.30	$187.30
Purchase #6	$112.37	13.686%	$127.749	$127.75	$127.75	$127.70
Purchase #7	$73.69	3.809%	$76.4969	$76.50	$76.50	$76.50
7 purchase totals =	$925.44		$1,010.9682	$1,010.97	$1,010.95	$1,010.90