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	$162.96	6.740%	$173.9435	$173.94	$173.95	$173.90
Purchase #2	$10.91	5.380%	$11.497	$11.50	$11.50	$11.50
Purchase #3	$27.53	13.764%	$31.3192	$31.32	$31.30	$31.30
Purchase #4	$49.59	4.805%	$51.9728	$51.97	$51.95	$52.00
Purchase #5	$207.73	4.362%	$216.7912	$216.79	$216.80	$216.80
Purchase #6	$138.57	8.628%	$150.5258	$150.53	$150.55	$150.50
Purchase #7	$145.48	10.380%	$160.5808	$160.58	$160.60	$160.60
7 purchase totals =	$742.77		$796.6303	$796.63	$796.65	$796.60