Wow! Thanks, SagaPer! This is way more than I asked.. looks like your view over the Volvo (complicated!) reality is pretty complete. But it also confirms a little bit my idea, i.e. that Volvo is all but clear and sharp in this context. In a "normal world", i.e. in a world where the payment of >40K€ for a car compares with professionalism and customer care, I'd expect that Volvo (and not the good willing Volvo Owners, and Facebook readers and forum administrators only) makes clear and easy to find + easy to read documentation available to all owners.
That is the reason why I now call Volvo a "chinoswedish" company... it brings the glorious name of the glorious Swedish Company, but it sometimes behaves as a pure chinese company. This is just my opinion, as a little owner of a Volvo car, that may be my first and last Volvo...