If you want to have similar effect to switchLights "OFF". !!! UNTIL IT GETS FIXED !!!
It will look a bit strange, lamps will switch off and disappear into thin air, but it looks way better than just setting the setDamage to the lights.
Use the above script with (_lampPost hideObject true;) instead of (_lampPost switchLight "off";) first and (_lampPost setDamage 1;)second without any sleep commands.
!!! Using setDamage only turns the lights off but shows damage animation !!!