the reason Jerry calls Kramer "Kessler" is because on Kramers buzzer the name kessler is on it. the reason for the name still to be there, is because of the kind of person kramer is, he would not want people to know who he really is, and well we all know how kramer is........so that is why the Kessler name is not removed from the buzzer. kessler must be for the person before hand, who lived in kramers apartment before him.
thankyou guide man !
medamnit