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	$86.71	10.662%	$95.955	$95.96	$95.95	$96.00
Purchase #2	$19.39	12.733%	$21.8589	$21.86	$21.85	$21.90
Purchase #3	$111.56	6.749%	$119.0892	$119.09	$119.10	$119.10
Purchase #4	$95.64	3.673%	$99.1529	$99.15	$99.15	$99.20
Purchase #5	$113.98	9.851%	$125.2082	$125.21	$125.20	$125.20
Purchase #6	$212.71	10.676%	$235.4189	$235.42	$235.40	$235.40
Purchase #7	$120.60	6.628%	$128.5934	$128.59	$128.60	$128.60
7 purchase totals =	$760.59		$825.2765	$825.28	$825.25	$825.40