Low Quality Model despite Level of Detail setting

I was testing out the Aerometrex Denver Photogrammetry tutorial at Using Custom Controllers | cesium.com

However, my models look a lot more low quality than the tutorial example, even though my settings are identical, level of detail set to 2. May I know if anybody got a solution to this?

I have attached some photos to show the difference.
(my version)

(tutorial screenshot)

The detail on that level is nicest only in that one area close to the station. As you go away from the station, the data is coarser. This is the case for everyone.