Holy Moly, let me explain what happened.
The guy who told you it will cost Rs 5000 is not in fact the fee for NADRA. What he is offering is the Lahore driving license made without any change of address on NADRA card for Rs. 5000.
I am very well aware of all these things. I know someone who got his Islamabad license made paying the agent Rs. 5000 without the need of changing address on NADRA Card. However, the license showed Islamabad address. What these agents do is they put a temporary address that you live in the city where you are applying. The credit card like driving license shows only Address. nothing more.
The guy who wanted Rs. 5000 is honest. He will get the whole thing done and get you Lahore driving license made in just one day. Even you won't have to stand in line and give a driving test. Just stand for few minutes near the test vehicle or sit inside and then come out and you are passed. No hassles and refusals. cuz they got money in pocket.
It is 100% legal procedure they adopt. But no need to change NADRA present address. Perhaps its they way the Govt employees make in collaboration with agents sitting outside saying it is mandatory in law to change NADRA address first while applying for driving license.