It is possible for someone who came on 16th to have received their PR card before someone who landed on the 12th as someone who landed without an address for the PR card to be sent would then need to establish an address before being able to sort the PR Card out. It is currently taking 53 working days as was told to my friend. We landed on 15th May and have received ours and this is despite changing our address from that provided at port of entry. Received cards on 20th of this month.
It will turn up just depends on how quickly everything was sorted out from your end. Good luck!!!