Yes, all seems to be correct, but I can not do what I want.
I think the way vShere handles its object is different in v6.5 than 6.0. Yes, I want to get inspired by your section 'Organize Your Disaster Recovery' to migrate all the inventory from a vCenter 6.0 to a new vCenter 6.5. I thought it was smart but in fact it was naive !
Thanks again for your time, I learnt lot of things readin this chapter (and other).