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	$191.41	4.390%	$199.8129	$199.81	$199.80	$199.80
Purchase #2	$190.68	5.721%	$201.5888	$201.59	$201.60	$201.60
Purchase #3	$205.28	6.139%	$217.8821	$217.88	$217.90	$217.90
Purchase #4	$248.44	5.792%	$262.8296	$262.83	$262.85	$262.80
Purchase #5	$29.82	13.543%	$33.8585	$33.86	$33.85	$33.90
Purchase #6	$36.29	3.427%	$37.5337	$37.53	$37.55	$37.50
Purchase #7	$84.93	11.402%	$94.6137	$94.61	$94.60	$94.60
7 purchase totals =	$986.85		$1,048.1193	$1,048.11	$1,048.15	$1,048.10