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	$88.40	7.545%	$95.0698	$95.07	$95.05	$95.10
Purchase #2	$242.98	13.411%	$275.566	$275.57	$275.55	$275.60
Purchase #3	$164.54	4.292%	$171.6021	$171.60	$171.60	$171.60
Purchase #4	$250.88	5.433%	$264.5103	$264.51	$264.50	$264.50
Purchase #5	$10.84	10.351%	$11.962	$11.96	$11.95	$12.00
Purchase #6	$217.63	9.490%	$238.2831	$238.28	$238.30	$238.30
Purchase #7	$102.64	11.574%	$114.5196	$114.52	$114.50	$114.50
7 purchase totals =	$1,077.91		$1,171.5129	$1,171.51	$1,171.45	$1,171.60