As part of the process, careful rituals must also be performed to inscribe runes and litanies into the armour. This requires a Hard (–20) Scholastic Lore (Occult) or Forbidden Lore (Imperial Creed) test for each location.

Are both skills at -20 or just the Scholastic Lore (Occult) part?

Thanks

Wakrob

You might have a better chance of sending the question in for official answer here:

https://www.fantasyflightgames.com/en/contact/rules/

Thanks. I sent one their way.