Another time I was feeling a bit grotty after a session and the verdict was a floating t/a ! Surely a mistake!
Well now I think I can help on this. As I recall, an exam is done at a fixed sensitivity. 8? I don’t know a reference on this. I just checked a reference on this, PC Examiner HCOB 21 April 1980R. There is no mention of sensitivity.
Now if you switch from a Mark VI e-meter to a Mark VII super variable sensitivity thing, the difference is quite marked. You may have done E-meter drill 5RB (can squeeze) with loads of people using a Mark VII and seen how low you had to set the sensitivity when the TA was a bit high (above 3.0). It was quite a shock for me, at first, having to set the sensitivity at 1.
So if at exams you set the sensitivity on a Mk VII up at 8, that is going to be
way too high for people nearer to 3.0 on the TA, especially with cold cans making the TA even higher. Therefore the needle is potentially going to hit the pins both sides. Nobody has ever heard of a pin-to-pin ARCX needle, so they may call it a floating TA!
Just remember that the Mk VII didn’t exist when the bulletins were written and nobody is allowed to change them
... or interpret them.