I have been using PowerChute 9.0, uninstalled to install the new 188.8.131.526. After that I realized that Windows Power Options disappeared. I guess that it's to prevent confusions between witch program decide when to Shutdown the machine? but in my case I was using Windows' options for the settings. This is because on a blackout I set the PC to reduce CPU usage, turn off the HDD and turn off the Monitor in few minutes so the UPS can hold more time till the electricity comes back.
There is an option for disabling Shutdown on Low Battery in PowerChute managing page, but can't enable the Windows Power Options to lower the energy use and to Hibernate on Low Battery.
Hope there is a way to re-enable it, or at least for the future versions of PowerChute to have this option.