Display powers off 5 seconds before Modern Standby entry on lock. What triggers it?

Hi, I'm investigating a "quirk" I have noticed related to VIDEOCONLOCK .

I've found a consistent 5-second gap between the display powering off and Modern Standby entry when VIDEOCONLOCK > 5s, and I'm trying to understand what causes it.

Environment: Windows 11 laptop, Intel, Modern Standby

STANDBYIDLE is 0 on AC, so standby is driven entirely by VIDEOCONLOCK.

Results across different VIDEOCONLOCK values

VIDEOCONLOCK Display off Standby Offset
1s 1s 1s 0s
2s 2s 2s 0s
3s 3s 3s 0s
4s 4s 4s 0s
5s 5s 5s 0s
6s 1s 6s 5s
7s 2s 7s 5s
10s 5s 10s 5s
20s 15s 20s 5s
60s 55s 60s 5s

During the offset, pressing a key brings the lock screen back instantly (no standby wake delay), so the system is still fully awake; just the display is off.

Event log findings

  • Kernel-Power Event 506 fires at the standby moment, not the display-off moment.
  • Kernel-Power Event 566 skips a session state on wake (e.g. 145→147, 142→144), suggesting an intermediate "display off, system active" state that never gets its own 566 event.
  • No events from any Windows provider have been found at the display-off moment.

Questions

  1. Is this 5-second offset hard-coded in the power state machine?
  2. Is there any way to configure it?
  3. Has anyone seen documentation on this?

/Michalis