Just to back up Hotrod yes that's correct. However there's no
restriction for the Co MEL to impose the FL315 restriction on
the newer ones if it sees fit. I flew a newie not long ago which
had this limitation in the TL.
Why I don't really know.
...you can continue with a single pack even in an ETOPS scenario. The decision is yours.
I'd be very twichy going over shark-ridden waters on a dark
and stormy night. A long ETOPS trip likely means you are
limited on fuel anyway, and the FOB at ETP2 is probably a lot
less than you'd like in the all-engine depressurised case.