14 ft. deep oceans

Can anyone point me to a thread that will give instructions on how we can tell the engine to allow us to make the ocean deeper on a Megatterrain map? I mean, not using the greyscale heightfield and re-generating the terrain, but actually using the manual world editor GUI and excavating the terrain lower. We have apparently hit a maximum depth of 14 feet for our ocean and we can't figure out how to make it deeper without also making the mountains significantly higher (via regenerating the terrain) and also, this method really does a number on the edge seams so I would really rather not go that route if at all possible.

What is happening?
We can raise and lower the terrain to a specific depth, and then it flattens out. We even tried raising the entire terrain 200 units above 0. This did not help. The seabed remains stubbornly at 14 feet deep, and will not go any lower than that, regardless of overall terrain elevation. The terrain itself seems to be hard coded with a specific depth. Is there any way around this? I don't see how to do it in script.

This is what our Megaterrain looks like right now

new SimGroup(MegaTerrain_N34E32_02) {
         canSaveDynamicFields = "1";
         Enabled = "1";

         new TerrainBlock(N34E32_02a) {
            canSaveDynamicFields = "1";
            Enabled = "1";
            position = "-2048 -2048 200";
            rotation = "1 0 0 0";
            scale = "1 1 1";
            detailTexture = "Visions/data/terrains/details/detail1.png";
            terrainFile = "Visions/data/missions/Kourion_0.ter";
            squareSize = "8";
            tile = "0";
            detailDistance = "25";
            detailScale = "256";
            detailBrightness = "1";
            texelsPerMeter = "8";
            clipMapSizeLog2 = "10";
         };
         new TerrainBlock(N34E32_02b) {
            canSaveDynamicFields = "1";
            Enabled = "1";
            position = "-0 -2048 200";
            rotation = "1 0 0 0";
            scale = "1 1 1";
            detailTexture = "Visions/data/terrains/details/detail1.png";
            terrainFile = "Visions/data/missions/Kourion_1.ter";
            squareSize = "8";
            tile = "0";
            detailDistance = "25";
            detailScale = "256";
            detailBrightness = "1";
            texelsPerMeter = "8";
            clipMapSizeLog2 = "10";
         };
         new TerrainBlock(N34E32_02c) {
            canSaveDynamicFields = "1";
            Enabled = "1";
            position = "-2048 0 200";
            rotation = "1 0 0 0";
            scale = "1 1 1";
            detailTexture = "Visions/data/terrains/details/detail1.png";
            terrainFile = "Visions/data/missions/Kourion_2.ter";
            squareSize = "8";
            tile = "0";
            detailDistance = "25";
            detailScale = "256";
            detailBrightness = "1";
            texelsPerMeter = "8";
            clipMapSizeLog2 = "10";
         };
         new TerrainBlock(N34E32_02d) {
            canSaveDynamicFields = "1";
            Enabled = "1";
            position = "0 0 200";
            rotation = "1 0 0 0";
            scale = "1 1 1";
            detailTexture = "Visions/data/terrains/details/detail1.png";
            terrainFile = "Visions/data/missions/Kourion_3.ter";
            squareSize = "8";
            tile = "0";
            detailDistance = "25";
            detailScale = "256";
            detailBrightness = "1";
            texelsPerMeter = "8";
            clipMapSizeLog2 = "10";
         };

Any ideas, suggestions or feedback? Please? Point me to a thread that has the magic solution that I couldn't find?

Thank you!
-Laurene