Submarine and submerge question

@Krieghund rules clarification question:

In the original Axis and Allies: Europe ('99), the submarines ability to submerge is not negated by a destroyer. Only the first strike is negated by a destroyer (and of course, a DD allows aircraft to hit subs).

Since “submerge” is never negated in this version, I am assuming that at least one round of combat must be fought before a defending submarine can submerge, right? Otherwise, the piece is indestructible on defense.

Just want to make sure of this. @kwaspek104 and I are playing a game and I’m considering attacking his sub with my sub. (sub v. sub)

@krieghund I’m currently working with TripleA to have Pacific and Europe tuned up to be in accordance with OOB rules. In that spirit…

@kwaspek104 and I have a slight curve-ball for you, a real one this time I think: In Pacific this aspect of the game is clear:

“Attacking Separately
When Allied units in the same territory (or sea
zone) wish to attack, each attacker must do so
only with his own units and only on his own turn.
Each player moves his units into combat on his
turn and resolves combat. It is possible for one
player to attack a sea zone that has both Allied
and enemy units present. In this situation, the
Allied units may be taken as casualties but they
do not participate in the combat.”

There follows an example confirming the rule.

In Europe however, all that is written is this:

“Attacking separately: When Allied units in the same territory
(or sea zone) wish to attack, each attacker must do so only with
his own units and only on his own turn. Each player moves his
units into combat on his turn and resolves combat.”

There is no example or anything I see in the manual to make me believe that allied units can be taken as casualties, but on page 2 of the FAQ it appears to infer the ruling of Pacific:

Q. When German subs are attacked in a zone that contains Allied naval units of more than one
nationality, Allied losses can be taken from any of those Allied vessels. If the defending
German subs score more hits than the attacking player has ships, must the excess hits be
taken from the Allied ships that are standing by? For example, a sea zone is occupied by three
German subs and two British transports. The US player brings in two destroyers and attacks
the subs. The German player rolls his defensive dice and scores three hits! Must the Allies
lose three ships, even though the Americans attacked with only two?
A. A guiding principle throughout the rules is that if there is a way to apportion hits so they result in losses, the losses must be taken. In this case, the Allies must lose three ships; whether those are two destroyers and a transport or two transports and a destroyer is up to the Allied players.

Can you confirm that the case in Pacific is true for Europe as well? Thank you! (I will use this thread as a reference for the developers if needs be)

@Krieghund additional question. Does the presence of an enemy industrial complex in a territory qualify as “occupied” in the context of blitzing with an armor.