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	$196.73	8.607%	$213.6626	$213.66	$213.65	$213.70
Purchase #2	$25.42	7.528%	$27.3336	$27.33	$27.35	$27.30
Purchase #3	$48.34	11.589%	$53.9421	$53.94	$53.95	$53.90
Purchase #4	$97.39	8.466%	$105.635	$105.64	$105.65	$105.60
Purchase #5	$67.33	9.680%	$73.8475	$73.85	$73.85	$73.80
Purchase #6	$11.41	9.649%	$12.511	$12.51	$12.50	$12.50
Purchase #7	$196.96	10.439%	$217.5207	$217.52	$217.50	$217.50
7 purchase totals =	$643.58		$704.4525	$704.45	$704.45	$704.30