It will be horrible if they change the bio-dad back to Nick and not Jack. After all this they are going to make Sharon out of a monster, turn Jack's world upside down, and make Nick a saint after all he did. Even if she changed the test, Nick still lied for 18years. I hope they do the right thing this time and give Jack his daughter.
Maybe Jack is also Faith's father and that is the test Sharin changed.