I think it's fair to say that CO is not getting any more information out of USCIS than we are - and is equally frustrated.
His only advantage is that he does know how many visas have been used to date, but he only knows that as they are approved by USCIS and doesn't have any insight into future demand or any USCIS processing priorities.
For EB, that's a big problem, since USCIS process 90% of cases. I'm not surprised the message is rather confusing.
EB1 seems to be the most clear, to the point where Worldwide applicants have started to downgrade to EB2, which is still current.
FB is interesting. CO has good visibility of the numbers in the queue and all categories have been retrogressed to date. It seems applicants there are reevaluating whether they want to emigrate to the USA at all, possibly based on the negative atmosphere towards FB immigrants at the moment.
Because most FB categories are highly retrogressed and are consular processed, CO does have the ability to move both the FD and FAD forward by large amounts to generate demand and process them in time. Having said that, some under-utilization in FB is starting to look possible, which would help EB in FY2020.