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	$219.59	4.450%	$229.3618	$229.36	$229.35	$229.40
Purchase #2	$222.59	10.144%	$245.1695	$245.17	$245.15	$245.20
Purchase #3	$232.77	9.788%	$255.5535	$255.55	$255.55	$255.60
Purchase #4	$239.38	11.763%	$267.5383	$267.54	$267.55	$267.50
Purchase #5	$225.39	13.148%	$255.0243	$255.02	$255.00	$255.00
Purchase #6	$61.46	6.658%	$65.552	$65.55	$65.55	$65.60
Purchase #7	$225.92	8.197%	$244.4387	$244.44	$244.45	$244.40
7 purchase totals =	$1,427.10		$1,562.6381	$1,562.63	$1,562.60	$1,562.70