You can try this if you like. I run on a Standard (Non-Admin) login in Win10. I have to apply the icon packages twice:
1st time, launch Icon Packager using the right-click "Run as administrator" option. Apply the icon package I'm wanting to apply. (This will also change the icons on the administrator login, in case it matters.)
2nd time, launch Icon Packager normally and apply the same icon package.