Smartbill is a romanian invoice manager with a strong integration in multiple frameworks. For Prestashop they have a module made by them which allows the user to emit invoices and keep accounting data.
The client sometimes made an invoice in Smarbill and he needed that the new stock to be synchronized back with the website. Say you sell 2 items of product X, then the stock on the website should now be current product X stock - 2. Unfortunately Smartbill has no module for that purpose, but it has a triggering mechanism to the user website with the stock updates. This can be setup in My account -> Integrations -> Stock synchronization.
Using the Smartbill triggering mechanism, we created a module that is able to target products based on their reference code and update the stock for them. This module is available with version Prestashop 1.6. Given the fact that the matching needs to be accurate we suggested unique reference numbers for each products and its combinations. The module provides reports with the matching outcome, so that the user can anytime choose to update website data, thus increasing the matching.