Product model need to quickly find the product in the base.
And if the products have options (eg volume)?
And each option has its own model number?
In OpenCart it was not envisaged to change the product model, depending on the options.
But now it is possible.
If you select to set the product model - now the new always appears instead of the old.
The only condition - to avoid confusion, use only one group of options to specify the article.

Adds a field "model" in the table oc_product_option_value.
Run the sql-script in the database.
Before running the script do not forget to change the table prefix (if you are not a standard).
Copy add_model_to_option-oc_2-1-0-1.xml file to a folder with VQMod.
That's all.

Created on OpenCart 2.1.0.1, VQMod 2.5.1, Default Theme.