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	$190.28	3.143%	$196.2605	$196.26	$196.25	$196.30
Purchase #2	$236.47	4.555%	$247.2412	$247.24	$247.25	$247.20
Purchase #3	$87.28	3.451%	$90.292	$90.29	$90.30	$90.30
Purchase #4	$84.32	7.420%	$90.5765	$90.58	$90.60	$90.60
Purchase #5	$107.96	4.649%	$112.9791	$112.98	$113.00	$113.00
Purchase #6	$10.83	6.697%	$11.5553	$11.56	$11.55	$11.60
Purchase #7	$100.79	5.155%	$105.9857	$105.99	$106.00	$106.00
7 purchase totals =	$817.93		$854.8903	$854.90	$854.95	$855.00