Same problem with my Windows 8.1 Thinkpad 10. "Sleep" and "Turn off display" are both the same thing! It's frustrating if you want to listen music.
Microsoft want to compete with Android? - Keep dreaming... They can't even fixed this very basic problem. Should have an update in the next business day!
Anyway, as temporary fixed, I set the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Power\CSEnabled to 0. This will disable the sleep function and turn-off the display instead. The disadvantage is I need to shutdown my computer if I want to turn it off.
I have the same problem on Acer Iconia W4-820 : Screen OFF and Tablet Sleep are related.
My poor solution was : Put a black screen saver ... and Sleep OFF (power parameters)
The screen is black, the Tablet stay ON but the lighting back remains ON.
I never, unwanted Sleep function on my Tablet. Your solution is right for me:
With the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Power\CSEnabled to 0
a new power setup is created... "Energy Saving" and is fully parameterizable
ScreenOFF =>Screen OFF with delay (Sleep function is disabled)
CoverOFF => do nothing =>Screen OFF with delay (Sleep function is disabled)
PowerButton=>Hibernation
The over personal parametters for 'Energy Saving' are memorised in advanced parameters power setup even after reboot. GOOD !!!
Now I can listen to music with Screen OFF and hoof closed. GOOD !!
!
Many Thanks