Life boat mod question re: abandoning ship

[K-61]

I love the life boat mod! It's great to see some human life in the game and it adds drama to your sinkings. I do have one question, in light of my experience from a goodly number of sinkings:

If you see a crew taking to the lifeboats, does that mean the ship will definitely sink? Several times I have seen lifeboats spawned but the ship sailed on and I have never received a sinking report, even after hanging around for many hours. In my last patrol I attacked two ships with my last three eels: one into an empire freighter and two into a large merchant, which sunk. The empire freighter took on a list and fell way behind the convoy. I would have finished her off with my deck gun [Jan. 42 so I still have one but can't use it anymore] but she was bristling with a naval gun and two menacing looking AA guns, too much firepower for me to risk my boat and crew. I had to let her go and she sailed merrily on her way.