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	$10.96	3.822%	$11.3789	$11.38	$11.40	$11.40
Purchase #2	$28.64	13.303%	$32.45	$32.45	$32.45	$32.50
Purchase #3	$202.97	3.159%	$209.3818	$209.38	$209.40	$209.40
Purchase #4	$62.29	4.371%	$65.0127	$65.01	$65.00	$65.00
Purchase #5	$94.30	9.595%	$103.3481	$103.35	$103.35	$103.30
Purchase #6	$93.64	5.287%	$98.5907	$98.59	$98.60	$98.60
Purchase #7	$164.72	12.234%	$184.8718	$184.87	$184.85	$184.90
7 purchase totals =	$657.52		$705.0340	$705.03	$705.05	$705.10