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	$195.67	10.293%	$215.8103	$215.81	$215.80	$215.80
Purchase #2	$223.89	11.867%	$250.459	$250.46	$250.45	$250.50
Purchase #3	$198.32	8.736%	$215.6452	$215.65	$215.65	$215.60
Purchase #4	$40.97	5.427%	$43.1934	$43.19	$43.20	$43.20
Purchase #5	$15.50	9.240%	$16.9322	$16.93	$16.95	$16.90
Purchase #6	$199.62	7.329%	$214.2501	$214.25	$214.25	$214.30
Purchase #7	$93.76	12.364%	$105.3525	$105.35	$105.35	$105.40
7 purchase totals =	$967.73		$1,061.6427	$1,061.64	$1,061.65	$1,061.70