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	$196.55	5.860%	$208.0678	$208.07	$208.05	$208.10
Purchase #2	$172.97	5.177%	$181.9247	$181.92	$181.90	$181.90
Purchase #3	$67.90	6.490%	$72.3067	$72.31	$72.30	$72.30
Purchase #4	$189.83	9.496%	$207.8563	$207.86	$207.85	$207.90
Purchase #5	$160.97	11.491%	$179.4671	$179.47	$179.45	$179.50
Purchase #6	$53.83	13.796%	$61.2564	$61.26	$61.25	$61.30
Purchase #7	$107.69	5.682%	$113.8089	$113.81	$113.80	$113.80
7 purchase totals =	$949.74		$1,024.6879	$1,024.70	$1,024.60	$1,024.80