The core issue is "everyone maintains their own copy": manufacturers have their own Excel, importers have their own quotation, and distributors re-enter the data from scratch when they receive it. If one step gets a number wrong, everyone downstream is working with incorrect data.
A more practical approach is to centralize product data, quotation terms, and trade documents in one source, so that partners at all levels read from and update the same data, rather than maintaining separate copies. Specifically: product specs and pricing are updated once at the source, and corresponding customers or distributors immediately see the latest version; when a quotation is sent, a version record is kept, and if the other party requests changes, you can directly compare the two versions instead of relying on memory or digging through old emails.
This approach requires all roles to access the same platform—including your customers and suppliers—otherwise the concept of "one single source" falls apart.