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	$69.34	4.836%	$72.6933	$72.69	$72.70	$72.70
Purchase #2	$137.75	4.846%	$144.4254	$144.43	$144.45	$144.40
Purchase #3	$31.43	5.762%	$33.241	$33.24	$33.25	$33.20
Purchase #4	$107.75	7.292%	$115.6071	$115.61	$115.60	$115.60
Purchase #5	$214.89	7.769%	$231.5848	$231.58	$231.60	$231.60
Purchase #6	$169.43	12.255%	$190.1936	$190.19	$190.20	$190.20
Purchase #7	$234.62	13.209%	$265.611	$265.61	$265.60	$265.60
7 purchase totals =	$965.21		$1,053.3562	$1,053.35	$1,053.40	$1,053.30