Back in Colorado, my farrier tried that toe-nail move on a paint mare with the same problem. She ended up with a tiny crack in the hoof wall from the change in stress (or so he said). He went back to the old pattern and just used a different type of shoe for her. Sometimes the fix isn't in the nails.
Yeah that paint mare story is rough. Alexc93 might be onto something with the heel move, but sometimes farriers just gotta stop experimenting and pick a lane.