Why don't AME's do audiogram on class 2 medicals when they feel a person doesn't hear properly.
Instead they come to me, FE, with a form for me to asses them in the aircraft.
I should not be asked to make a judgement, it's up to the AME to use appropriate equipment to asses the person.
For instance they could use a headset fed with sample radio calls and say morse code.
I am biased, i don't want to lose a customer (flying club) by saying they are ok when they a have obvious hearing problems.