By default, Windows will only automatically update its time from an NTP server if the Windows computer's time is within 15 hours of the correct time. It's possible for an image to load and the computer's time be off by more than this value. Registry settings can be adjusted to allow the time to update regardless of skew:
Improving the chances that the time is correct will increase the chances that KMS activation will succeed, a step which occurs later on in the post-load stage. Activation fails if the computer's time is incorrect.