6. If the Imam mistakenly stands for an extra rak'ah before completing the required final sitting, the follower does not follow him; the follower waits and reminds him.
7. In this technical case, if the follower ends his own prayer with Salaam before the Imam has tied the extra rak'ah to a Sajdah, the source states that the follower's Fard is invalid.
8. It is Makruh Tahrimi for the follower to give Salaam after the Imam has completed Tashahhud but before the Imam himself gives Salaam.
These are technical follower rules. They should be taught exactly, without simplifying them into 'always follow every movement' or 'never wait for the Imam.'