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	$199.64	7.495%	$214.603	$214.60	$214.60	$214.60
Purchase #2	$175.86	8.376%	$190.59	$190.59	$190.60	$190.60
Purchase #3	$154.47	11.742%	$172.6079	$172.61	$172.60	$172.60
Purchase #4	$170.98	10.539%	$188.9996	$189.00	$189.00	$189.00
Purchase #5	$82.64	3.423%	$85.4688	$85.47	$85.45	$85.50
Purchase #6	$156.43	3.570%	$162.0146	$162.01	$162.00	$162.00
Purchase #7	$9.44	7.873%	$10.1832	$10.18	$10.20	$10.20
7 purchase totals =	$949.46		$1,024.4671	$1,024.46	$1,024.45	$1,024.50