Block world collision problems

[java]CollisionShape sceneShape = CollisionShapeFactory.createMeshShape((Node) data);
landscape = new RigidBodyControl(sceneShape, 0);

    data.addControl(landscape);[/java]  this code works to the point that it creates a block collision mesh that the Y+ side works fine and lines up with the objects added to the data node but the Y- side are wrong. The block collision mesh ends up being 2 blocks high with the block I actually want being the top one. Am I just setting up the Mesh wrong or is this just a weirdness with my setup? (the only think added to the data node is Block geometries). And on a side note, is there anyway to convert the node to a collision mesh that is as low poly as possible? thanks in advance! :D