Can't get a consensus what a cutof reading on a B&K 465 means

[Chris K]

On their YouTube channels, both Shango66 and Bob Andersen have the Super Mack and celebrate a tube as having good cutoff if the needle deflects more than a quarter of way up the scale when switched to gun balance. The B&W/Red pot should be turned all the way up when switching to gun balance and then adjusted down to the gun balance line on the meter. That's done before switching to emissions to test that. Using the sencore and the 465 as I've seen them used, the tube I'd considered good was good on both and the bad tube was bad on both. I have a pristine NOS 10bp4 that shoots the needle 3/4 of the way up the meter when switched to gun balance. Maybe I'll put that on the 465 and check how it reads. It produces a fantastic picture.