Good stuff, I'll use your format, with several notes.
Mount = Weapon
First note. Mount does not equal Weapon. A weapon mount = a mount for a weapon. However for the purposes of rules interpretation, when a mount is discussed, it in effect is refering to a single weapon or weapon system. A factor 9 missile weapon system (of many missiles) may be mounted in a bay.
Second note. If mount = weapon, each individual weapon becomes a battery. This is a given from the Turret Weapons table, it follows the format provided in Book 2 and it ensures backwards compatability in rules. (ie: MM's requirement that Book2 ships must be usable in HG battles.)
If you take Mount = Weapon, then the following arrangements are legal:
a)One triple turret operated as 3 batteries of 1 missile weapon
b)Two triple turrets operated as 6 batteries of 1 missile weapon
c) Three triple turrets operated as 9 batteries of 1 missile weapon
c1) Any combination of turrets, mounting 10 missile weapons, operated as 10 batteries of 1 missile weapon
and the following arrangements are illegal - where there are more than 10 weapons of the same type:
d) Four triple turrets operated as 12 batteries of 1 missile weapon
e) Five triple turrets operated as 15 batteries of 1 missile weapon
etc...
Mount = Turret
Third note: If Mount = Turret then the entire turret must be a battery. (or grouped into larger turret batteries.) I don't think there is much debate on this, it is at the core of the arguement for Mount = Turret.
Forth note: Turrets come in 4 types. Single, Dual & Triple configurations and Barbettes. The phrase "Missile Turret" is used within the rules only in examples to describe the contents of a turret, not the turrets "type". (Note 1, Turrets rules)
Now spend a minute or two on re-reading
"Ships with more than ten mounts of the same type must group them into batteries." And if you conclude 'this is silly', I agree. I leave it to others to justify.
Nope, on previewing this I won't take the chance that you will pause. Here it is spelled out.
"Ships with more than ten mounts of the same type must group them into batteries."
equals
"Ships with more than ten triple turrets must group them into batteries." Feel free to swap "triple turret" with Single, Dual or Barbette.
If the arguement is that 'of course' a Missile turret is a type of turret, this then falls down with the turret type 'Mixed' forcing that arguement to rely on the 'mixed turret rule' to in effect re-instate what the first two lines state anyway (with the correct reading). This leads to more strangeness, like laser, sand and missile = ok. But my missile supplier cannot provide missile, missile, missile. Ohh, but there goes free Trader Beowolf, with exactly what I want. Whats that, no I can't have that for my navy? Why not...
If you take Mount = Turret, , then the following arrangements are illegal:
a)One triple turret operated as 3 individual missile batteries
b)Two triple turrets operated as 6 individual missile batteries
etc...
If you take Mount = Turret, , then the following arrangements are all legal:
1) One triple turret operated as a missile battery.
2)Two triple turrets operated as a missile battery
3) Three triple turrets operated as a missile battery
4) Four triple turrets operated as a missile battery
5) Five triple turrets operated as a missile battery
6) Six triple turrets operated as a missile battery
7) Seven triple turrets operated as a missile battery
8) Eight triple turrets operated as a missile battery
9) Nine triple turrets operated as a missile battery
10) Ten triple turrets operated as a missile battery
and the following arrangements are illegal:
11) Eleven triple turrets.
13) Thirteen triple turrets
As "Ships with more than ten mounts of the same type must group them into batteries." and neither 11 nor 13 (& other prime numbers) are divisible into smaller groups.
And for those whom may insist on promoting "Missile turret" as a turret 'type'.
the following arrangements are illegal:
11) Eleven missile turrets.
13) Thirteen missile turrets
As neither 11 nor 13 are divisible into smaller groups.
All food for thought.
Matt
Note 1.
"Turrets are installed on hardpoints with single, dual, and triple configurations, and allow the mounting of lasers (...etc)"
Book 5 page 30