Dell Thunderbolt Dock TB16 Maximum Cable Length

I have a Dell Thunderbolt Dock TB16 - 240W docking station for the XPS 15 9560. It comes with a 0.5m USB Type-C Thunderbolt cable. Is there a longer cable, such as a 1m cable available for the TB16?

The TB16 was shipped from Dell with an instruction booklet entitled "Thunderbolt 3 (USB Type-C) Dock Cable Installation Guide." The book has instructions on how to remove the shipped cable and replace it with some cable that is received as a separate shipment. Does anyone know the purpose for those instructions? 

I'd like to suggest that the above questions would be a nice addition to the TB16 FAQ... adding some info on cable length, cable length restrictions, future plans for differing cable lengths, etc., might help users such as myself. I see others out there which have concerns about short cable length so that's why I think the answer to the above would make good TB16 support KB articles or FAQ entries. 

Thank you!