^^^^^^^^^^
IDK perhaps his snake had a bigger diameter. Power snakes also rotate and move back and forth. Who knows

Ran three loads through it today whilst keeping an eye on it when it drained. Not so much as a hiccup.

It's a mystery.

Your plumber probably did as I do and bends the end of his snake. This way it opens a big spot in the plug instead of a little hole that easily plugs back up. Showed this technique to a customer just last week.