Products are only added to Mailchimp when they are created, yet are still attempted to update

(This is all for Commerce, not ubercat)

Currently, the only place I can find that adds a product & variations to mailchimp is the function:

mailchimp_ecommerce_add_product()

Which is called by:

/**
 * Implements hook_commerce_product_insert().
 */
mailchimp_ecommerce_commerce_commerce_product_insert()

Because of this, the module won't add existing products to mailchimp.

The real problem happens when updating these existing products.

mailchimp_ecommerce_update_product()

Is called from:

/**
 * Implements hook_commerce_product_update().
 */
function mailchimp_ecommerce_commerce_commerce_product_update()

Which fires every time a product is saved. So now the module is trying to update a product on Mailchimp's side, failing because it doesn't exist there, and sets a big red error message of "404 - the requested resource could not be found" which is confusing drupal admins:

mailchimp_ecommerce_log_error_message('Unable to update product: ' . $e->getMessage());

I propose two things to fix this:
First, on product_update, a check should be put in place if the product exists on Mailchimp. If it doesn't, then it should create it. This could even be done by the exception handler - if it returns a 404, it should create the product then.

Secondly, all the drupal_set_message(ERROR...) should check the log level before displaying a big red error. Everything is already logged, so why is it displaying big errors without checking if it should? Something like

if (variable_get('error_level', ERROR_REPORTING_HIDE) != ERROR_REPORTING_HIDE) {
  drupal_set_message(ERROR...)
}