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	$162.80	11.680%	$181.815	$181.82	$181.80	$181.80
Purchase #2	$23.54	3.342%	$24.3267	$24.33	$24.35	$24.30
Purchase #3	$116.69	13.665%	$132.6357	$132.64	$132.65	$132.60
Purchase #4	$207.92	5.849%	$220.0812	$220.08	$220.10	$220.10
Purchase #5	$27.96	10.798%	$30.9791	$30.98	$31.00	$31.00
Purchase #6	$188.32	4.114%	$196.0675	$196.07	$196.05	$196.10
Purchase #7	$242.25	7.443%	$260.2807	$260.28	$260.30	$260.30
7 purchase totals =	$969.48		$1,046.1859	$1,046.20	$1,046.25	$1,046.20