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	$91.91	3.289%	$94.9329	$94.93	$94.95	$94.90
Purchase #2	$30.64	10.248%	$33.78	$33.78	$33.80	$33.80
Purchase #3	$222.61	13.734%	$253.1833	$253.18	$253.20	$253.20
Purchase #4	$174.55	5.807%	$184.6861	$184.69	$184.70	$184.70
Purchase #5	$193.59	6.191%	$205.5752	$205.58	$205.60	$205.60
Purchase #6	$187.60	4.763%	$196.5354	$196.54	$196.55	$196.50
Purchase #7	$39.60	9.138%	$43.2186	$43.22	$43.20	$43.20
7 purchase totals =	$940.50		$1,011.9115	$1,011.92	$1,012.00	$1,011.90