add_filter('kleo_pmpro_level_restrictions', 'my_custom_levels');

function my_custom_levels($kleo_pay_settings) {
    $kleo_pay_settings[] = array(
            'title' => __('New Option A','kleo_framework'),
            'front' => __('Option A','kleo_framework'),
            'name' => 'new_option_a'
        );
    $kleo_pay_settings[] = array(
            'title' => __('New Option B','kleo_framework'),
            'front' => __('Option B','kleo_framework'),
            'name' => 'new_option_b'
        );
    $kleo_pay_settings[] = array(
            'title' => __('New Option C','kleo_framework'),
            'front' => __('Option C','kleo_framework'),
            'name' => 'new_option_c'
        );
    return $kleo_pay_settings;
}