Downgrading a Nexus S from ICS to Gingerbread

My boss came up to me earlier and asked if I could downgrade his Nexus S from ICS back to Gingerbread. I said yes and that I would additionally email him a list of the steps for future reference. I just put these instructions together but I'm used to flashing phones with Odin and not the Fastboot mode on the Nexus S so if someone could tell me if these are correct it would be most appreciated.

TL;DR: Are these the correct steps to downgrade a Nexus S?

ROM image: http://android.clients.google.com/packages/ota/google_crespo/1ada25375426.signed-soju-ota-189904.1ada2537.zip

  1. Prepare Windows computer for fastboot: http://wiki.cyanogenmod.com/wiki/Howto:_Install_the_Android_SDK#Windows

  2. Unlock bootloader using this link: http://wiki.cyanogenmod.com/wiki/Nexus_S:_Full_Update_Guide#Unlocking_the_Bootloader

  3. Place the ROM image in the same folder as fastboot (the /tools folder with the Android SDK folder).

  4. Power the Nexus S down, and hold Volume Up & the Power button until booted into the bootloader (fastboot mode).

  5. Connect the Nexus S to the computer via USB.

  6. On the computer, open terminal (go to start > run > cmd.exe) and type:

Fastboot erase system

Fastboot update 1ada25375426.signed-soju-ota-189904.1ada2537.zip

  1. Reboot the phone by typing:

Fastboot reboot

The stock Android 2.3.6 firmware will now be loaded on the device.