Above one's paygrade

Hello,

Can we use "above one's pay grade" when someone doesn't have the ability/skill to do something? For example:

- I do know a bit about mechanics, but I can't help you fix your truck. That's way above my paygrade.

- Going toe to toe with someone as powerful as him was just above my grade.

If I am not mistaken, it was originally used in military contexts meaning "I am too junior to decide about something", but I am not sure. Macmillan dictionary defines it as "not having the authority to decide about something".

Thank you.