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	$177.28	10.693%	$196.2366	$196.24	$196.25	$196.20
Purchase #2	$14.51	11.667%	$16.2029	$16.20	$16.20	$16.20
Purchase #3	$13.78	6.649%	$14.6962	$14.70	$14.70	$14.70
Purchase #4	$188.96	3.763%	$196.0706	$196.07	$196.05	$196.10
Purchase #5	$140.41	4.207%	$146.317	$146.32	$146.30	$146.30
Purchase #6	$107.95	8.819%	$117.4701	$117.47	$117.45	$117.50
Purchase #7	$96.77	3.819%	$100.4656	$100.47	$100.45	$100.50
7 purchase totals =	$739.66		$787.4590	$787.47	$787.40	$787.50