Yes, but the link to the internal regulations page doesn't actually go to an "internal regulations" page. It goes to an "Aikikai Activities" page which has a load of yearly plans, subsidiary aid reports and information on registering dojos and even forms on how to fill in the forms etc. It isn't a section that explains rules for obtaining any rank or instructor qualification.
I don't think the absence of an internal rules page at the end of the link and interviews/statements from 10-20 years ago (during which the system has changed) prove that there is a double standard now. Note that dan and kyu grades are in the same situation as the instructor qualifications: there are no internal regulations listed for them either, because the link just goes to "activities". Does this mean that there are double standards for kyu grades and yudansha too then?
How about asking Mr Tani what the situation is now and if the only rules shown (the international ones) apply to everyone? Regarding the value of the rank, as with Aikikai recognition for dojos, the official position is pretty clear:
Obviously simple recognition for these purposes will mean different things to different people but is it necessary that the labels come with special privileges or powers?
Much of what appears on the Aikikai's Japanese web page in the bottom group under the heading 「合気会とその活動」 is in response to recent change in Japanese law concerning tax free foundations. There are no longer any branch dojos (支部) of the Aikikai (except the Iwama Dojo, which is the Ibaraki shibu) and each dojo/group has to apply for 登録 and or 公認. If the dojo is on the list appearing on the Aikikai's Japanese website, it already has 登録. Kounin 公認 is supposed to be an 'added value' title and can be part of the dojo name, rather like Japanese driving schools.
Apart from the requirements of the change of law, I think all this represents an attempt to tidy up a chaotic organization in Japan and give some flesh to the phantom existence of the All-Japan Aikido Federation. My understanding is that in all of the 47 prefectures a prefectural federation (県合気道連盟) is established and all the 公認 dojos in a prefecture belong to this organization. All the prefectural federations will be members of the All-Japan Aikido Federation.
As you are aware, nothing at all is mentioned on the Aikikai's Japanese website about teaching ranks. Only the minimum dan ranks are specified. However, if you have a large organization like the All-Japan Aikido Federation, with branches all over Japan, then you can establish proper teaching titles, like shihan and shidoin, and also criteria for the award of such teaching titles. At present, the ranks of 6th dan and 8th dan in aikido appear to correspond to the ranks of mokuroku
in traditional Japanese arts. So all my Japanese neighbours know that if you have 6th dan, you are a shihan. This is a situation that the Aikikai would love to regulate.