Knot cinching on bill hook tongue. NH 276

Working on a NH 276; it was missing too many bales at the end of last year; it was cinching the knot on the bill hook tongue; I had rounded the tooth on the tongue and shortened it a bit; I loosened bill hook tension. It would miss a couple ties per hundred; it I did not catch it in time, it would have two or three strings hung on bill hook.

I replaced bill hooks and set tension to spec. I also loosened tension from twine box to 10# (it was @30# tension with needles at top of needle stroke; an old manual called for 5-15# in this position)
I have adjusted knife arm to max (½” past bill hook) and it had acceptable pressure/rub on bottom of bill hook... it is wiping the bottom fine.

Everything I seem to do makes it worse and I have been chasing any possible cause, but am out of ideas.

Yup, I searched the forum first with negative results; I re-read Mike10's pinned posts... no specific luck; even googled the crap out of it... no love.

Thanks, Mark

Knot cinching on bill hook tongue. NH 276