Binding primitives to a controller works only for the constructor

I bound a primitive value to a class.

$this->app->when('App\Http\Controllers\TestController')
            ->needs('$numPages')
            ->give(1000);

But this value is injected only to the constructor of the class, and not to other methods.

class TestController extends Controller
{
    public function __construct($numPages = 0)
    {
        // $numPages = 1000  WORKS
    }

    public function index($numPages = 0)
    {
        // $numPages = 0  DOESNT WORK
    }
}

But when I bind a normal class, its instance is injected in all methods. Is it intended behavior?