Well, thanks for your quick response ! and sorry for my english (just read my previous post...)
Actually, I already got 75K miles (not status ones) so 90K miles more would allow me a nice ticket (depending on availability yes, but that will be a way to test amex concierge service) . Besides, i could then ask for a lower fee to amex for renewal next year, considering amount spent previously (I can't be 100% sure but reading the dedicated threat in amex plat forum, i believe amex would make an effort) .

But you are probably right regarding the possibility for amex & paypal to detect this kind of movement...
and yes... FB plat may not worth this effort/cost