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.
At least they're not charging for the Shihan certificate. However if I subscribe to National Geographic for 10 years and then want to change to subscribe to Nature Magazine then don't usually ask me to backdate my subscription by 10 years
The costs for the certificates are what they are - they all charge a similar amount. It's the backdating thing that gets me. Probably should be in another topic / thread tho.
Sorry for taking it off topic