Lag in History Updates

I've written a job to pull a list of recordings using the LstRecording XML API.  I then pull the list of Attendees for each meeting using the LstmeetingattendeeHistory XML API.   I'm noticing a weird thing.

It appears the recording shows up quickly but I've seen it take hours for the list of attendees API to return anything after the meeting.  I've changed the end date in the Recording API call to be one day earlier but I want to see how much is really needed to make sure all the date is there.

     string endString = DateTime.Now.AddDays(-1).ToUniversalTime().ToString("MM/dd/yyyy HH:mm:ss");

Historical data takes 48-72h before it becomes available; its not realtime.