It does work as before, but with a subtle differences.
As mentioned above the command line is changed, and looks like normal patch command lines.
This is hiding what is actually happening, which is that the patch files are created in "%programdata%\symantec\patch\InstallationSandbox#date and time" and a batch file called Windows10x64Professional1803.iso_install.bat is running - the contents of which are remarkably similar the the batch file used in previous feature updates.
Question is where is it and how would I modify this batch file if I needed to on NS?