Specification Manager (XSR) role for T&M industry

Hello,

I was studying the "[Eng to Mfg Best Practices] Make From" in relation of a specific customer (train manufacturer).

I discovered that according to Portfolio Navigator, the XSR role is not available for T&M industry.

Is this a mistake or is there a reason for this?

Is there any other way to create Raw Material object in the platform than with an XSR role?

Thank you.