Should TIMESTAMP be required when publishing nightlies

[sxa]

There is a conflict between two parts of the process.
In the refactor release tool job it says Optional timestamp to add for nightly builds. against the description of the TIMESTAMP field
But if you try to run without a TIMESTAMP set the job says Nightly must have a TIMESTAMP set
Is it optional, or is it mandatory? Either way, the messages need to be consistent with each other.