Haroon, you need to check with your Flight Operations Engineering department, and they probably with Airbus.
It makes no sense, and I think the explanations provided so far are valid for something else than you asked about.
To reiterate my understanding of your original question:
In case you needed to apply the speed corrections for low QNH, the resulting V2 is invalid. How come?
Last edited by FlightDetent; 23rd May 2019 at 14:54.
Reason: undone auto-correct