OK, now I'm really lost...
Anyway, Saotome (for example) has been calling his folks "shihan" for years without any approval (or interference) from hombu. I suppose that it's an internal title, but does it matter?
When I started Aikido back in the 70's, Saotome Sensei told us that 6th Dan was the same as Shihan. In the sense that he has used the term, it was interchangeable with "master instructor". He has, upon occasion, referred to me as a Shihan. But we have no certificates and it is not any type of "official" title. We do not use the Fukushidoin, Shidoin, Shihan teaching certificate system used by the Federation. I have a Shidoin certificate from the days when I ran a dojo that was under Chiba Sensei back in the 80's but has never had any meaning within our organization.
The whole point of teaching certificates is to recognize that people will get Dan Ranking as a result of time in grade. If you look at Judo they have Hanshi, Renshi, and Kyoshi certifications for teaching which are a separate issue from Dan Rank.
I can tell folks that the titles do matter. Most dojos are affiliated with an organization of some type. The members within such an organization naturally give priority to attending seminars with whomever is the head of that organization. After that, they tend to flock towards the teachers who are perceived to be the closest in relationship to that teacher. It can have little to do with actual teaching ability. There can be highly skilled teachers who exist on the periphery because they have not been "anointed" by the "big guy". Titles and ranks are a sign that a certain teacher is "in favor" with the powers that be and the members of that organization consequently invest in that teacher far more than they do any other teachers.
I believe that the entire structure of American Aikido will change when the current generation of uchi deshi passes away. That process has already started. When they are no longer presiding over the art here, it will be the senior American students who will take the reins. It will matter greatly what their ranks and titles are when they begin to assume central leadership roles. I do not think, however, that it will matter one iota whether those ranks and titles are recognized in Japan as long as they were conferred by someone with recognized authority here.
Ranks and titles just give one "access". Folks are impressed by them whether it makes sense or not. So it can get you in the door so to speak. But once someone invites you to teach or attends one of your classes, you better be able to deliver the goods. That is true now and it will be more true when the current leadership passes on and my generation is left on its own. But the ranks and titles are what gives you your shot at reaching the students in the first place.