The variance involved in converting cups of flour to grams is much greater than any gravitational variances caused by elevation or location. So that's sort of irrelevant here.

This is a great second argument for using weight not volume for measurements.
Measuring mass is of course not viable, but measuring weight in a consistent location means all the ratios end up correct. While ratios between volume and weight measured substances change (and flour probably compacts differently).
That is why one should always use a scale to measure their fluids, and why metric is superior where 375ml of water or milk are 375g (convert the recipe ahead of time at a reference location), making this trivially easy.

If you wish to then correct the total mass of your dish, you can simply compare the weight and volume of water to work out the mass to weight ratio and correct accordingly.