autoship_enable_lock_duration_restriction

(src > schedule-orders.php) Can be used to apply or remove the lock duration restrictions. The filter value is true by default.

Example

 // override lock restriction
function xx_override_lock_restriction($current_value){
    return $current_value = false;
}
  add_filter('autoship_enable_lock_duration_restriction', 'xx_override_lock_restriction', 10, 1);

lock duration restriction