You don't know that the term handashi applies to a koshirae, not a sword, and you don't know how to read a signature
. For an NBTHK-recognized expert and polisher, that's not good enough.
https://www.proantic...11440-handashi.html#
For your diploma, the organization's last kanji is different, the stamp doesn't match and neither does the color, and I've never seen an official NBTHK document with so many ink smudges.
An expert as you claim to be finds something interesting that is not at all traditional, you're a clown.
https://www.proantic...11475-wakizashi.html
What did Laurent die of?