I would suggest that you should get the equivalence made in anycase, but HEC will only give you an equivalence / recognition letter after you get your actual degree, as i understand it.
I am uncertain regarding the need for O and A level equivalences but then again with FPSC it is my opinion that you should always go for the safer option.
Submit everything you can and get the rest made along the way over the course of time.

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There is a tide in the affairs of men. Which, taken at the flood, leads on to fortune; Omitted, all the voyage of their life Is bound in shallows and in miseries. On such a full sea are we now afloat, And we must take the current when it serves, Or lose our ventures. ~ William Shakespeare