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	$92.64	12.209%	$103.9504	$103.95	$103.95	$104.00
Purchase #2	$67.79	11.866%	$75.834	$75.83	$75.85	$75.80
Purchase #3	$198.38	3.380%	$205.0852	$205.09	$205.10	$205.10
Purchase #4	$125.80	4.429%	$131.3717	$131.37	$131.35	$131.40
Purchase #5	$147.73	12.738%	$166.5478	$166.55	$166.55	$166.50
Purchase #6	$171.30	4.757%	$179.4487	$179.45	$179.45	$179.40
Purchase #7	$199.72	12.431%	$224.5472	$224.55	$224.55	$224.50
7 purchase totals =	$1,003.36		$1,086.7850	$1,086.79	$1,086.80	$1,086.70