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	$196.86	5.687%	$208.0554	$208.06	$208.05	$208.10
Purchase #2	$208.88	6.730%	$222.9376	$222.94	$222.95	$222.90
Purchase #3	$240.96	9.522%	$263.9042	$263.90	$263.90	$263.90
Purchase #4	$26.96	12.367%	$30.2941	$30.29	$30.30	$30.30
Purchase #5	$46.57	13.659%	$52.931	$52.93	$52.95	$52.90
Purchase #6	$164.68	7.155%	$176.4629	$176.46	$176.45	$176.50
Purchase #7	$198.54	7.727%	$213.8812	$213.88	$213.90	$213.90
7 purchase totals =	$1,083.45		$1,168.4664	$1,168.46	$1,168.50	$1,168.50