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	$89.88	6.746%	$95.9433	$95.94	$95.95	$95.90
Purchase #2	$68.27	6.211%	$72.5102	$72.51	$72.50	$72.50
Purchase #3	$208.57	3.537%	$215.9471	$215.95	$215.95	$215.90
Purchase #4	$175.94	6.145%	$186.7515	$186.75	$186.75	$186.80
Purchase #5	$75.44	8.817%	$82.0915	$82.09	$82.10	$82.10
Purchase #6	$21.77	4.273%	$22.7002	$22.70	$22.70	$22.70
Purchase #7	$106.51	4.746%	$111.565	$111.57	$111.55	$111.60
7 purchase totals =	$746.38		$787.5088	$787.51	$787.50	$787.50