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	$178.39	10.390%	$196.9247	$196.92	$196.90	$196.90
Purchase #2	$5.66	4.682%	$5.925	$5.93	$5.95	$5.90
Purchase #3	$173.85	10.471%	$192.0538	$192.05	$192.05	$192.10
Purchase #4	$41.46	5.182%	$43.6085	$43.61	$43.60	$43.60
Purchase #5	$197.40	11.708%	$220.5116	$220.51	$220.50	$220.50
Purchase #6	$217.39	3.404%	$224.79	$224.79	$224.80	$224.80
Purchase #7	$152.43	6.790%	$162.78	$162.78	$162.80	$162.80
7 purchase totals =	$966.58		$1,046.5936	$1,046.59	$1,046.60	$1,046.60