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	$85.95	11.609%	$95.9279	$95.93	$95.95	$95.90
Purchase #2	$172.83	12.746%	$194.8589	$194.86	$194.85	$194.90
Purchase #3	$187.48	8.545%	$203.5002	$203.50	$203.50	$203.50
Purchase #4	$39.51	9.816%	$43.3883	$43.39	$43.40	$43.40
Purchase #5	$160.49	10.656%	$177.5918	$177.59	$177.60	$177.60
Purchase #6	$149.50	11.789%	$167.1246	$167.12	$167.10	$167.10
Purchase #7	$137.90	9.396%	$150.8571	$150.86	$150.85	$150.90
7 purchase totals =	$933.66		$1,033.2488	$1,033.25	$1,033.25	$1,033.30