don't think QP offer WIA, they may offer someone a currency fluctuation allowance but as an American citizen you are not eligible as the US$ is pegged to the QAR and therefore suffers no fluctuations.

As I said QP grades are almost certainly not assigned based on each individual person but on the role itself in isolation. This will have already been estabslished a long time ago. An HR job evaluation expert or an exerternal organisation set these using any number of different scales, I gave examples - Watson and Wyatt or Hay are 2 that I know of.

Also, if they already have people doing the same job with the same credentials, they cannot put you on a different grade - why should they? what you can argue for is increased salary within said grade citing your experience and qualifications (I would not mention the fact that you are a US citizen, it really will make no difference).

Also, I doubt they would have made the offer based on your current location, they will ask your point of origin, which you will correctly state is the US, if they as for further proof, all you have to do is send them a copy of your passport.

I have to say, your posts do have a whiff of paranoia, personally I would not approach your negotiations in this way, it will only set HR's backs up. Please note they deal with overseass hires on a daily basis, you are not unique to them.