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	$173.52	10.570%	$191.8611	$191.86	$191.85	$191.90
Purchase #2	$49.78	8.552%	$54.0372	$54.04	$54.05	$54.00
Purchase #3	$119.68	7.683%	$128.875	$128.88	$128.90	$128.90
Purchase #4	$129.32	6.536%	$137.7724	$137.77	$137.75	$137.80
Purchase #5	$213.95	7.674%	$230.3685	$230.37	$230.35	$230.40
Purchase #6	$101.76	12.794%	$114.7792	$114.78	$114.80	$114.80
Purchase #7	$140.61	11.513%	$156.7984	$156.80	$156.80	$156.80
7 purchase totals =	$928.62		$1,014.4918	$1,014.50	$1,014.50	$1,014.60