Half way down the page you have
The misinformed docs
Warning
If you turn on the Save Contents as Locked option in the operator type properties, you cannot save custom operators with any locked operators (for example, locked SOPs or CHOPs).
I think it should read
The soon to be changed docs
Warning
If you turn off the Save Contents as Locked option in the operator type properties, you cannot save custom operators with any locked operators (for example, locked SOPs or CHOPs).