Your question seems to be based on the assumption that only one of the lenses would cause reduction?
If her left lens caused it, so would her right lens.
Yes, that would seem to confirm what people have been saying lately, that WHCC's quality is slipping.
Nothing changes. You need to calibrate such that your screen matches your lab's prints. The numbers are somewhat meaningless.
Good grief, you don't use Curves for that, and you definitely don't use the black eyedropper.
http://www.damiensymonds.net/2013/02/using-photo-filter-layer-to-fix-casts.htm