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	$197.28	13.520%	$223.9523	$223.95	$223.95	$224.00
Purchase #2	$66.62	6.712%	$71.0915	$71.09	$71.10	$71.10
Purchase #3	$147.43	3.514%	$152.6107	$152.61	$152.60	$152.60
Purchase #4	$142.27	3.802%	$147.6791	$147.68	$147.70	$147.70
Purchase #5	$154.47	4.786%	$161.8629	$161.86	$161.85	$161.90
Purchase #6	$228.60	7.534%	$245.8227	$245.82	$245.80	$245.80
Purchase #7	$55.62	10.199%	$61.2927	$61.29	$61.30	$61.30
7 purchase totals =	$992.29		$1,064.3119	$1,064.30	$1,064.30	$1,064.40