The image depicts 'LoS to target -2°", not "LoS to the horizon -2°", which is what you claim. Draw a line from the plane to the horizon (tangent to the sphere) then lean it down two degrees more, where does it point now? I'd make the drawing for you but I need to eat, see you all laterI hope an image is worth a thousand words:
Not to scale, but mathematically accurate. Just an example, there could be many other scenarios for the cloud, like being higher just below the plane, but much shorter in length.