Base Map Distance no longer supports over 2000?

In previous versions of Unity I have been able to adjust the Base Map Distance of my terrain beyond 2000 but now it doesn't seem to allow me to. I'm using large scaled terrain and my mountains are appearing very blurry from a short distance even at 2000. I've tried adjusting it through code ( Which has worked in the past to push it past 2000 ) but now I'm not having any luck getting it to work.

Code (csharp):

1.  
2. function Start () {
3. Terrain.activeTerrain.basemapDistance = 10000;
4. }
5.