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	$40.85	7.652%	$43.9758	$43.98	$44.00	$44.00
Purchase #2	$112.98	10.622%	$124.9807	$124.98	$125.00	$125.00
Purchase #3	$210.69	6.548%	$224.486	$224.49	$224.50	$224.50
Purchase #4	$168.78	12.801%	$190.3855	$190.39	$190.40	$190.40
Purchase #5	$105.32	10.140%	$115.9994	$116.00	$116.00	$116.00
Purchase #6	$242.98	11.171%	$270.1233	$270.12	$270.10	$270.10
Purchase #7	$44.87	4.430%	$46.8577	$46.86	$46.85	$46.90
7 purchase totals =	$926.47		$1,016.8084	$1,016.82	$1,016.85	$1,016.90