WPF unsmooth double-animation

I read quite a few questions about choppy animations here but sadly none have solved my issue.

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I have a window and under some circumstances (checkbox check) the window height should increase or decrease.

I wrote a small method for the animation and when the checkbox is checked it executes the method.

public static void NewWindowHeight(MainWindow MainWindow1, int Height)
{
    double oldheight = MainWindow1.Height;
    DoubleAnimation animation = new DoubleAnimation(oldheight, Height, TimeSpan.FromSeconds(0.2));
    MainWindow1.BeginAnimation(MainWindow.HeightProperty, animation);
}

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I have two checkboxes and at a defined combination the window height should be set to a specific value. This is the code behind the checkbox_clicked method. (I only show this one because it is basically the same code with the other checkbox)

private void CheckBoxSetup_Click(object sender, RoutedEventArgs e)
{           
    if (CheckBoxSetup.IsChecked == false && CheckBoxUpdate.IsChecked == false)
    {
        MethodsClass.NewWindowHeight(MainWindow1, 180);
    }
    if (CheckBoxSetup.IsChecked == true || CheckBoxUpdate.IsChecked == true)
    {
        MethodsClass.NewWindowHeight(MainWindow1, 220);
    }
    if (CheckBoxSetup.IsChecked == true && CheckBoxUpdate.IsChecked == true)
    {
        MethodsClass.NewWindowHeight(MainWindow1, 260);
    }
}

All works well, but the animation is kinda choppy. Not terrible but definetily not smooth. What could be the reason for this? How could i solve this?

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Some pictures for better understanding: