Aligning a quad to Kinect v2's FloorClipPlane

Hello,

I'm making an AR project that involves getting the floor plane and inserting 3D objects into the scene with the correct perspective and orientation applied.

To do this, I'm taking the BodyFrame.FloorClipPlane Vector4 property (Ax + By + Cz + D = 0) and applying the normal (A, B, C) to my plane. I've cross-referenced this to the plane produced by a 3D point cloud and it seems that my calculated plane is about 15 degrees off.

Is there a conversion from Kinect space to world space that I'm overlooking? Has someone tried this project before and would like to offer advice?

Thanks