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	$161.80	8.445%	$175.464	$175.46	$175.45	$175.50
Purchase #2	$20.36	4.691%	$21.3151	$21.32	$21.30	$21.30
Purchase #3	$22.42	11.378%	$24.9709	$24.97	$24.95	$25.00
Purchase #4	$214.98	9.301%	$234.9753	$234.98	$235.00	$235.00
Purchase #5	$37.92	11.629%	$42.3297	$42.33	$42.35	$42.30
Purchase #6	$144.31	4.277%	$150.4821	$150.48	$150.50	$150.50
Purchase #7	$208.62	3.765%	$216.4745	$216.47	$216.45	$216.50
7 purchase totals =	$810.41		$866.0116	$866.01	$866.00	$866.10