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	$91.54	4.714%	$95.8552	$95.86	$95.85	$95.90
Purchase #2	$194.90	8.296%	$211.0689	$211.07	$211.05	$211.10
Purchase #3	$35.46	5.824%	$37.5252	$37.53	$37.55	$37.50
Purchase #4	$163.28	12.647%	$183.93	$183.93	$183.95	$183.90
Purchase #5	$213.59	9.653%	$234.2078	$234.21	$234.20	$234.20
Purchase #6	$229.59	10.253%	$253.1299	$253.13	$253.15	$253.10
Purchase #7	$29.31	6.675%	$31.2664	$31.27	$31.25	$31.30
7 purchase totals =	$957.67		$1,046.9834	$1,047.00	$1,047.00	$1,047.00