I would also agree with your statement the lack of support from the organization.
There was a context to my question that might not immediately be clear.
I do not think that the fact of a large organization like the Aikikai directly impinges on the grading tests in the average dojo. In fact, one of the distinctive features of the Aikikai used to be that it is not at all the name of a style of aikido. The second Doshu, Kisshomaru Ueshiba, had a distinctive way of doing aikido, but this was not shared by the senior instructors within the Aikikai. I was directly taught by some of these senior instructors and I learned at first hand how different they were. In the years before I became a yudansha, I trained at four different dojo, each with a distinctive way of executing kihon waza. So, from very early on I learned three important facts about aikido training at that time.
There are different way of executing the same waza.
There are different names for the same waza.
Different waza are sometimes requested in grading tests for the same kyu rank.
So I think the issue in your case lies at the point where the organization interfaces with the life of the local dojo. In my case, there is no interface, since I am the dojo-cho, and I have no organizational links with other local groups. However, the main group has a central dojo, with a shihan of 8th dan rank, and several satellite dojos, each with a local instructor. I used to be a member of this larger group and I have seen local instructors being roasted by the shihan because their way of doing the waza required for a particular kyu test was not the 'correct' way (= the way preferred by the 8th dan shihan). The students never failed, but the local instructor was severely chastised and some of the local dojos gained reputations for a poor level of technical training and instruction.