Dear Vibin
You are right we have two tabs which allow us to enter nozzle projection but please pay attention that each of them has a different meaning.
one of them is in the "nozzle main" tab and its lable is "nozzle outside projection". in this tab you must enter the length of nozzle neck.Indeed you just enter the length of nozzle without considering its flange.
(look at the defenition of "ho" in the following picture)
In The seconed tab which is placed under the "Layout" button in the "nozzle main" tab, you must enter the distance from the center of shell to the face of the flange.
(look at the defenition of "Proj" in the following picture)