Unfulfillable inventory due to PAO/expiration- please explain anyone!

Hello fellows,

I noticed 5 units of inevntory were moved to unfulfillable and queried it here. I later found out it was due to expiry dates the items were no longer up for sale...

Having asked support about this as they had no expiry date but PAO (period after opening) I got a response that doesn't make it any clearer and I would of course like to understand how this works.

They sent me the follwing response-

"This product expiry date cannot be removed due to the reason of PAO or Period After Opening. Period After Opening was introduced in 2005 for cosmetics as per the EU Cosmetics Directive. A product with an expiry date of 30 months or more will not need to display an expiry date. It requires only an indication as to the Period After Opening by the consumer during which it can be used. All products with an expiry date of less than 30 months will need to carry the expiry date on the packaging.

Know that items with PAO sing loses effectiveness over time and to prevent negative buying customer experience, items under Expired condition cannot be moved back to sellable condition if it present PAO Sign."

and gave em the follwing link https://sellercentral-europe.amazon.com/help/hub/reference/G201003420

I've read what they wrote, read about expiry dates on FBA, had a look at numerous products I have purchased from Amazon UK with 6M PAO (like the products I sent in) on them so I can't quite figure out what they are saying? PAO's work differently to expiry dates or not?

Thank anyone who can explain

And how do I get these units back- theres some settings to tweak so they return them to me rather than destroy/discard them?

TIA

T