谁能告诉我为什么这段代码的可维护性指数只有 40

我不知道为什么这种方法的可维护性指数（在Visual Studio中计算）只有40，我实际上必须删除除前两行之外的几乎所有行才能超过60：

    public void getNewPasswordDetails(Int32 newPasswordId)
    {
        int UserId = HttpContext.Current.User.Identity.GetUserId().ToInt();
        bool userIsAdmin = HttpContext.Current.User.IsInRole("Administrator");
        //get a list of userIds that have UserPassword records for this password
        var UserIDList = DatabaseContext.UserPasswords.Where(up => up.PasswordId == newPasswordId).Select(up => up.Id).ToList();
        //Retrive the password -if the user has access
        Password newPassword = DatabaseContext.Passwords
                                                        .Include("Creator")
                                                        .Where(pass => !pass.Deleted
                                                        && (
                                                            (UserIDList.Contains(UserId))
                                                         || (userIsAdmin && ApplicationSettings.Default.AdminsHaveAccessToAllPasswords)
                                                         || pass.Creator_Id == UserId)
                                                            )
                                                            .Include(p => p.Parent_UserPasswords.Select(up => up.UserPasswordUser))
                                                            .SingleOrDefault(p => p.PasswordId == newPasswordId);

        if (newPassword != null)
        {
            //map new password to display view model
            AutoMapper.Mapper.CreateMap<Password, PasswordItem>();
            PasswordItem returnPasswordViewItem = AutoMapper.Mapper.Map<PasswordItem>(newPassword);
            //generate a string based view of the new category
            string passwordPartialView = RenderViewContent.RenderViewToString("Password", "_PasswordItem", returnPasswordViewItem);
            //broadcast the new password details
            PushNotifications.sendAddedPasswordDetails(passwordPartialView, returnPasswordViewItem.Parent_CategoryId, returnPasswordViewItem.PasswordId);
        }
        else
        {
            //we dont have access any more, so tell UI to remove the password
            PushNotifications.sendRemovePasswordAccess(new PasswordDelete()
                                                                { 
                                                                     PasswordId = newPasswordId
                                                                });
        }
    }

DatabaseContext.Passwords
               .Include("Creator")
               .Where(pass => !pass.Deleted
                          && ((UserIDList.Contains(UserId))     // Why Check #1
                               || (
                                   userIsAdmin                // Why Check #2
                                   &&                        // Why Check #3
                                   ApplicationSettings.Default.AdminsHaveAccessToAllPasswords
                                  )
                              || pass.Creator_Id == UserId) 
                             )
               .Include(p => p.Parent_UserPasswords.Select(up => up.UserPasswordUser))
               .SingleOrDefault(p => p.PasswordId == newPasswordId);