Transfer from "1C: Enterprise 7.7" to "1C:Integrated Automation

What Is Implemented:
Also from the peculiarities of the project should be noted separate accounting, when part of the goods sold with VAT and part of the goods without VAT. In the typical solution separate accounting is not supported and had to add special modules. As a result, the company can work with different cash regimes.
Client:
The work was performed for Service-Auto LLC. The company sells spare parts and components, and also provides car repair services.
Problematics and Inquiry:
As is often the case, the system was originally filled with incorrect nomenclature data, there were a lot of duplicates and the balances were not displayed correctly. Before starting the work, I had to wipe out all the cards and only then transferred from the old system to the new one.