You are correct in that the database is only loaded periodically. This is the very busy time of year for the Registrar, as the calendar year for registrations ends on November 1st. Cultivars registered after Nov. 1 will be registered as 2016 registrations. There is no such thing as pre-registration, that was done away with years ago. Some people choose to reserve names before they register, but remember there is a cost to do this, so others will wait until they are ready to actually register and introduce the cultivars and take their chances that the name hasn't been selected. Anyone who registers should first do a search of the database to make sure that the name hasn't already been taken or that there isn't already a name that sounds too similar to what has been selected, as a very close name could also be rejected.
I expect the DB will probably not be reloaded with all the new entries until some time after Nov. 1st.
