Depth Under Keel

[Spike88]

I understand that the keel of a ship is the bottom of the ship. And when you ask for a depth under keel its not the depth of the water, but how much water is between you and the ocean floor.
Now my question is, when you ask for a depth under keel report from your navigator, is it always 100% accurate?

The reason I ask this is because I was trying to escape a destroyer, I had already taken moderate damage from depth charges which lead to flooding in the Torpedo room, and also in the two engine rooms. In an attempt to escape I decided to take us low. We were currently at 60 meters and I asked the Navigator for DUK, he reports 24 meters. Not wanting to get too close to the bottom, I order the crew to take us down to 70 meters. We're descending and I can hear the destroyer in the area depth charging close to us. All of a sudden there is a loud sound, and the crew is thrown around. My WO reports that we've taken more damage and that the flooding has worsned. I offcourse cheat and check the external view to see that we have hit the ocean floor. About a minute later we all die due to critical flooding. Is this due to the DUK report being inaccurate or just me making a poor calculation?