Dear Kunal
I am not agreeing with said opinion. Let's take example, MAWP of vessel = 5 MPa. There is nozzle on bottom d'end. Now assume vessel is running at MAWP. During is running condition Piping loads are acting on this nozzle.

This means, to fulfill above case WRC has to be performed at MAWP; otherwise Nozzle would fail at MAWP + Piping loading.