Upgrade 1.8 to 1.9- Q1. Any tips with - UpdateCustomer

if (BillingAddress == null)
{
  BillingAddress = 
    CustomerManager.InsertAddress(customer.CustomerId, true, 
      payerbilling.FirstName, payerbilling.LastName, payerbilling.Phone,
      payerbilling.PayerEmail, string.Empty, payerbilling.CompanyName, payerbilling.Address1, payerbilling.Address2, payerbilling.City,
      billingStateProvinceID, billingZipPostalCode, billingCountryID,
      DateTime.UtcNow, DateTime.UtcNow);
    customer = CustomerManager.SetDefaultBillingAddress(customer.CustomerId, BillingAddress.AddressId);
}

if (BillingAddress == null)
{
    BillingAddress = new BusinessLogic.CustomerManagement.Address()
    {
        CustomerId = customer.CustomerId,
        IsBillingAddress = true,
        FirstName = payerbilling.FirstName,
        LastName = payerbilling.LastName,
        PhoneNumber = payerbilling.Phone,
        FaxNumber = string.Empty,
        Email = payerbilling.PayerEmail,
        Company = payerbilling.CompanyName,
        Address1 = payerbilling.Address1,
        Address2 = payerbilling.Address2,
        City = payerbilling.City,
        StateProvinceId = billingStateProvinceID,
        ZipPostalCode = billingZipPostalCode,
        CountryId = billingCountryID,
        CreatedOn = DateTime.UtcNow,
        UpdatedOn = DateTime.UtcNow
    };

    IoC.Resolve<ICustomerService>().InsertAddress(BillingAddress);

    if (BillingAddress.AddressId != 0)
    {
        customer.BillingAddressId = BillingAddress.AddressId;
        IoC.Resolve<ICustomerService>().UpdateCustomer(customer);
    }
}