Okuyama's receipt of kyoju-dairi in Daito-ryu is nothing to sneeze at (given in absolute terms relative to the number of people Sokaku Takeda trained, this was a rare accomplishment), nor is the time he spent training directly with Takeda.
Also, a long-time publicly divulged core tenet of Hakkoryu's pedagogy is that "Hakkoryu unites martial arts and medicine so as to show clearly they are but one and the same". Given that Daito-ryu "aiki", as defined and/or expressed by any of the major legitimate lineages, is not reliant on shiatsu or kyusho-jutsu, it makes sense, as a licensed (Daito-ryu) aiki-jujutsu instructor, that Okuyama understood the difference between what he was teaching under Takeda's banner and what he planned to teach going forward -- and so chose his words carefully when branding his new art (of course, this does not mean that aiki was excluded as a notable aspect of Hakkoryu).
How far along did Okuyama progress in the Daitoryu curriculum? It is my understanding that he trained under a "journeyman" and not someone high-level. Did he progress past the Hiden Mokuroku? If Okuyama did have aiki skills derived from Daitoryu did he simply withhold teaching them?
Can your clarify your statement in regard to Daitoryu aiki not being reliant on shiatsu or kyusho? Are you implying that Okuyama may have possibly combined his shiatsu and kyusho with aiki he learned through Daitoryu training and developed a different flavor of "body skills"? If so, I find the concept fascinating.
Looking at the Hakkoryu curriculum it would make sense that Okyuama simply took what he learned of the Hiden Mokuroku and threw in some shiatsu/kyusho and called it a day.