Change order product quantity

Thank you for your great plugin. Hi, we are checking if, with you plugins, we can reach our main aim: create a multivendor ecommerce where a vendor can change the product order quantity, and the main aim is that the quantity can have DECIMAL value. So, when the vendonr admin change the quantity, the new subtotal has to change accordingly by calculate the new value as unit price * new quantity value.

Is that possibile with your plugin? thank you very much!