How do Qantas points and status credits post after a flight?

I travelled on QF43 Sydney-Denpasar this week with a relative. We were on the same booking, we boarded at the same time, we both have the same FF status, yet we received our points and status credits about 48 hours apart. This same thing has occurred several times this year. I am surprised by how inconsistent Qantas are at crediting points.

I would have assumed that after a flight a list of all the boarded passengers gets sent to a Qantas server which then credits the points. So I am a little confused why different passengers would receive points at different times, and why it sometimes takes a day for the points to credit and sometimes takes 3-4 days.