The Aluminium will have actually deflected more than that, but sprung back to its present position, as elastic deformation has taken place.
So the paint surface will have been subjected to much more bend than is currently visible.
...
Anyone with a knowledge of the yield strength of the actual Aluminium used (possibly Duralumin.) would be able to give the exact figures of how far the panel would have moved, to recover to its present position.
I doubt that scratches are the result of deformations in elastic range.
Scratches are as large as pitch between two rivets, an elastic deformation of this size is not possible. Metal sheet would give for sure under buckling or shear stresses
I guess scratches are the result of impact dynamics.