Was able to take a Dell copy of Windows 8, make an uefi bootable usb key, install onto my Dell, and also onto some acers in my office. It used the embedded keys each time, gave me 8 pro where appropriate, and 8 standard when appropriate. No hassles, activated immediately, no calls to robo activation at Microsoft. Good times.
Have you run Windows Updates on all the machines, if so any issues? From what you say it seems very close to piracy.