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	$59.49	4.759%	$62.3211	$62.32	$62.30	$62.30
Purchase #2	$18.83	4.336%	$19.6465	$19.65	$19.65	$19.60
Purchase #3	$189.56	3.509%	$196.2117	$196.21	$196.20	$196.20
Purchase #4	$37.97	10.457%	$41.9405	$41.94	$41.95	$41.90
Purchase #5	$226.63	10.817%	$251.1446	$251.14	$251.15	$251.10
Purchase #6	$48.72	13.553%	$55.323	$55.32	$55.30	$55.30
Purchase #7	$140.96	13.518%	$160.015	$160.02	$160.00	$160.00
7 purchase totals =	$722.16		$786.6024	$786.60	$786.55	$786.40