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	$89.35	7.365%	$95.9306	$95.93	$95.95	$95.90
Purchase #2	$90.73	11.212%	$100.9026	$100.90	$100.90	$100.90
Purchase #3	$105.97	11.723%	$118.3929	$118.39	$118.40	$118.40
Purchase #4	$13.36	4.428%	$13.9516	$13.95	$13.95	$14.00
Purchase #5	$172.35	6.551%	$183.6406	$183.64	$183.65	$183.60
Purchase #6	$158.46	9.733%	$173.8829	$173.88	$173.90	$173.90
Purchase #7	$142.30	13.104%	$160.947	$160.95	$160.95	$160.90
7 purchase totals =	$772.52		$847.6482	$847.64	$847.70	$847.60