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	$103.53	10.351%	$114.2464	$114.25	$114.25	$114.20
Purchase #2	$67.62	7.381%	$72.611	$72.61	$72.60	$72.60
Purchase #3	$212.65	10.299%	$234.5508	$234.55	$234.55	$234.60
Purchase #4	$213.46	11.669%	$238.3686	$238.37	$238.35	$238.40
Purchase #5	$45.89	13.356%	$52.0191	$52.02	$52.00	$52.00
Purchase #6	$120.59	3.763%	$125.1278	$125.13	$125.15	$125.10
Purchase #7	$174.30	6.690%	$185.9607	$185.96	$185.95	$186.00
7 purchase totals =	$938.04		$1,022.8844	$1,022.89	$1,022.85	$1,022.90