Clarification would be helpful. I was under the assumption that we enter the IRR for the period of time between when we swear in and when we arrive at OCS. However, upon re-reading the document I linked, that could also be interpreted as instructions for OCS applicants who are in the IRR (from prior service) at the time of application. Reading
Chapter 4 of the same manual indicates (on p. 31) that the NRD "completes enlistment documents and service agreement," with no indication of a timeline. My only personal concern is whether there is enough time between my swearing-in and my OCS date for my orders to be generated.
Again, I'm going to err on the side of trusting that my OR knows what he's doing; he has gotten me this far in the process, I have no reason to doubt his competence at this point.
This also demonstrates the danger of the Internet; I don't really have a lot of context for the information in this manual, which makes confusion or misinterpretation much more likely.