One thinks two powerplants will need to be replaced with new. Brown goo in an engine producing power most likely utterly destroyed #1's internals. That's 40 million plus, prior to entertaining a new wing. Even if possible to repair, one also thinks the damaged wing will not be retained. That's another 30 million, and then add up the damage done to Fuselage, Empennage, etc. Not unusual for an insuror to underestimate, it too has stockholders, and RR may face some counter claim by this firm. The lack of disclosure to the players 'softens' AON's indemnity, this will take a very long time to sort, IMO