You're right, that is worth bringing up, because there are in fact two distinct versions of
Fires of War being published, one for M&M 2E, the other for HERO 5E.
Later this year the original
Algernon Files will be updated to M&M 2E, but at the time that comes out there will be a HERO edition for it, too.
IMHO this is a good move by Blackwyrm Games, increasing their potential customer base substantially.