Yeah I gathered that after posting the question here. basically nayatel is charging for port forwarding and that IMO, is actually very pathetic on part of nayatel. While PTCL dose no such thing.
You don't need to buy a static IP from your ISP unless you are making some sort of a server at your end which requires an external static IP. For a simple port forward all you have to do is to give your machine an internal static IP and define your desired port in your modem and that's it.
Nayatel is just making side business with port by blocking them and opening some certain ranges for a monthly fee of 150rs/Month. That's very pathetic for charging something as meager as a port.
I am a long time PTCL user and now I also have Nayatel experince. And I must say, Apart from customer support, PTCL is far far better then nayatel in terms of value for your money.