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	$86.62	10.761%	$95.9412	$95.94	$95.95	$95.90
Purchase #2	$146.38	3.291%	$151.1974	$151.20	$151.20	$151.20
Purchase #3	$21.63	10.736%	$23.9522	$23.95	$23.95	$24.00
Purchase #4	$150.31	5.868%	$159.1302	$159.13	$159.15	$159.10
Purchase #5	$146.52	6.725%	$156.3735	$156.37	$156.35	$156.40
Purchase #6	$87.54	5.562%	$92.409	$92.41	$92.40	$92.40
Purchase #7	$250.89	9.399%	$274.4712	$274.47	$274.45	$274.50
7 purchase totals =	$889.89		$953.4747	$953.47	$953.45	$953.50