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	$219.68	11.862%	$245.7384	$245.74	$245.75	$245.70
Purchase #2	$70.39	8.153%	$76.1289	$76.13	$76.15	$76.10
Purchase #3	$213.92	7.701%	$230.394	$230.39	$230.40	$230.40
Purchase #4	$92.43	7.537%	$99.3964	$99.40	$99.40	$99.40
Purchase #5	$151.85	7.265%	$162.8819	$162.88	$162.90	$162.90
Purchase #6	$221.47	7.699%	$238.521	$238.52	$238.50	$238.50
Purchase #7	$68.72	3.505%	$71.1286	$71.13	$71.15	$71.10
7 purchase totals =	$1,038.46		$1,124.1892	$1,124.19	$1,124.25	$1,124.10