Slightly off topic but possibly related...
Hombu dojo seems on the whole to be there to make (or take) a lot of money for not very much. Unless I'm mistaken, in my own position, if I were to suddenly join Hombu dojo I'd have to pay for all of my dan grades again... Erm, why? My last 2 are ratified by a direct student of the founder. Ka Ching me thinks.
Do the Shihan certs cost money from Hombu like the dan certs? Ouch if so...
No charge, AFAIK.
If you break down promotion fees and average them out over years of practice you tend to get something similar to the membership fees in a professional organization. The question becomes, though, whether or not that organization is returning anything tangible in the way of benefits or resources.
IMO, for the Aikikai to be relevant in the coming years, these are issues that they will have to consider.