There’d’ve been no reason for her to switch amulets if that were the case.
My impression is that the Alicorn Amulet comes with a free download of every unicorn spell ever devised, and Trixie’s “that’s impossible!” was quite literal in the sense that she did not believe the spell was possible in any way.
The thing is, Trixie actually could have done an R63 spell. Everything that Twilight faked being able to do was actually something she could have done with the amulet.
There’d’ve been no reason for her to switch amulets if that were the case.
My impression is that the Alicorn Amulet comes with a free download of every unicorn spell ever devised, and Trixie’s “that’s impossible!” was quite literal in the sense that she did not believe the spell was possible in any way.