Runic AND SwdTech to Shock?

The Offering doesn't work like the other command-changing relics; X-Fight isn't its own separate command, the way that Sketch->Control or Slots->GP Rain. I don't recall off-hand how number-of-attacks is handled, but it's a distinct function from command-swapping.

(To answer the first part of the question, to have one relic change two different commands, you'd have to either use two different bits -- one per command being changed-from -- or a branch to a chunk of new code when checking one of the bits. Or completely rewrite the way that command-changing is handled.)