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	$216.56	10.649%	$239.6215	$239.62	$239.60	$239.60
Purchase #2	$59.69	3.822%	$61.9714	$61.97	$61.95	$62.00
Purchase #3	$60.51	5.409%	$63.783	$63.78	$63.80	$63.80
Purchase #4	$245.38	12.629%	$276.369	$276.37	$276.35	$276.40
Purchase #5	$171.89	8.760%	$186.9476	$186.95	$186.95	$186.90
Purchase #6	$106.66	4.630%	$111.5984	$111.60	$111.60	$111.60
Purchase #7	$96.85	8.761%	$105.335	$105.34	$105.35	$105.30
7 purchase totals =	$957.54		$1,045.6259	$1,045.63	$1,045.60	$1,045.60