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	$191.75	4.704%	$200.7699	$200.77	$200.75	$200.80
Purchase #2	$74.96	5.869%	$79.3594	$79.36	$79.35	$79.40
Purchase #3	$50.60	3.635%	$52.4393	$52.44	$52.45	$52.40
Purchase #4	$141.83	9.583%	$155.4216	$155.42	$155.40	$155.40
Purchase #5	$49.59	4.540%	$51.8414	$51.84	$51.85	$51.80
Purchase #6	$57.36	4.449%	$59.9119	$59.91	$59.90	$59.90
Purchase #7	$91.48	3.668%	$94.8355	$94.84	$94.85	$94.80
7 purchase totals =	$657.57		$694.5790	$694.58	$694.55	$694.50