Is this book
a retitled copy of Aikido Shugyo?
Nice find - although I don't particularly care for the title. Shioda was not particularly spiritual (by his account) and I think they added that as a marketing play more than anything.
That book looks like its pretty much going to be a retitled copy of Aikido Shugyo as you suggest. The same translators are credited. It will have 288 pages compared to Shugyo's 207 so there will be some additional content. I doubt the additional content will be previously unpublished portions of Shioda's autobiography but I would love to be wrong.
My advice would be to hold out for the new title - especially as it will be available in the UK sometime this year.