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	$125.97	11.813%	$140.8508	$140.85	$140.85	$140.90
Purchase #2	$134.41	13.752%	$152.8941	$152.89	$152.90	$152.90
Purchase #3	$158.41	8.589%	$172.0158	$172.02	$172.00	$172.00
Purchase #4	$106.67	3.661%	$110.5752	$110.58	$110.60	$110.60
Purchase #5	$180.30	8.348%	$195.3514	$195.35	$195.35	$195.40
Purchase #6	$120.87	7.816%	$130.3172	$130.32	$130.30	$130.30
Purchase #7	$112.64	9.613%	$123.4681	$123.47	$123.45	$123.50
7 purchase totals =	$939.27		$1,025.4726	$1,025.48	$1,025.45	$1,025.60