I think this is an overly confident position to take when you consider how things like carrier oil are known to change absorption rates of injectable AAS. It is recorded in medical literature that Nebido Test U absorbs slower due to the carrier oil used. If castor oil can slow the absorption of the hormone then of course the excipients/carrier oil used are relevant in the discussion of hormone release.
Suffice to say that both are relevant. Does BB speed up the release from the ester? Maybe, maybe not, but more BB relative to more carrier oil may make release from the ester *begin* more quickly, so the effect is the same as increasing the rate of ester breakdown.