TPG, XRF And Ungradable Details

As far as I know, the TPG's never provide any details of any scientific examinations on any coin that they may have done.

It would be good if they did do this, at the very least on what methods of non destructive testing they use, and under what circumstances they feel that these methods may be justified to use.

In not doing so, it seems to me that the TPG industry may be somewhat negligent.

It reassuring to know that at least some bullion dealers have XRF backup, so why not TPG's ?

Just knowing that a coin has been slabbed may be OK for authentication coins that have a potential market value (say) below $2,000,
but what about a coin that has a potential value of $50,000, and what particular method(s) were used?

Quite independently from TPG grading,
I have has a coin's surface examined under an electron microscope and a 50,000 volt non destructive electron beam metal analysis carried out at several points under a high vacuum, whilst under examination in the microscope's chamber.