Sure the altitudes amend the Dutchess Four clearance itself, but not the
clearence's explicit lost-comm procedure. That would only be amended if ATC
issued explicit lost-comm altitudes too.

But when ATC tells you "Maintain 3000, expect 4000 after 10," isn't "expect
4000" explicitly for lost-comm? From the AIM:

EXPECT (ALTITUDE) AT (TIME) or (FIX)- Used under certain conditions to provide
a pilot with an altitude to be used in the event of two-way communications
failure. It also provides altitude information to assist the pilot in
planning.

Barry