tsh:
By the way, is it certain that DRM is preventing the current watch now from working on the extender?
Yes - Netflix uses a non-silent license acquisition(which extenders do not support) and also does not allow the license to be stored on the computer which means extenders can not gain access to the license.
If I was to guess they do not store the license on the computer anymore because people were using the stored license to strip the DRM from their movie's.