First off, S-OFF is the term given to completely unlocking the device without using the HTC developer website and thus not notifying HTC that you have voided your warranty. S-OFF was only able to be done when the initial software was released on the phone. HTC fixed the exploit in an OTA so that users would have to use the HTC method.
Secondly, S-OFF and the HTC unlock method unlock the bootloader, which doesn't sound like what you are trying to accomplish. Root is something completely different. You must be rooted to unlock the bootloader, but you don't need to be unlocked to root.
Thirdly, the very first root thread I read on XDA has the following quote:
http://forum.xda-dev...d.php?t=1671577
If you have 1.22.651.3, you will have to wait for a little bit until the developers crack the newest OTA.