Just to add a little more confusion:
Arsenal Pg. 123, Main Guns states: "Unless otherwise noted, all of the following weapons can be
installed into Fixed Weapon Mounts or Heavy Turrets"
That means that even an Gauss Cannon can installed in a normal, fixed weapon mount (a light autocannon can even be installed in a flexible weapon mount, see the entry under light autocannon). That, or somebody forgot to write "reinforced".
Some lines later at the following page, under "Launch Weapons" : "The following weapons are large, self-propelled projectiles
that can be fired from specialized launch platforms or released from the wings of aircraft s and helicopters.
The interresting point here is that there is no mention of weapon mounts at all ( well, you can say maybe they confused launch platform with weapon mount, but to use 2 so different words for the same thing would be really stupid). The launch weapon attached to an aircraft is just realesed from its clamp, falls a little distance and then starts its engine, ne special mount needed.
The way i read it is that you just put launch weapons under a wing, in case of aircrafts, without the need for a weapon mount. Of course it can be stored in a weapon mount (for better concealment, for example).
In case of other vehicles you need a weapon mount (cars, ships...just drop a missile from a ship or a car und start it may be funny, but not wise).
So, question: Why do some vehicles (in this case a bomber) need 11 reinforced weapon mounts? The only answer that make sense and i can come up with is: 2 reinforced weapon mounts can hold 1 cruise missile, which can be found under "Cruise Missiles" in War! (i would like to mention the page, but i only possess the german version, which includes several additional content und different page numbers).
So, all in all: if you have a lot of weapon mounts, you can use 1 for some sort of cannon and the rest for other vehicle weapons, like the Hail Barrage (or even for single missiles). If you just have one or two weapon mounts you can use them for cannons and attach some missiles under the wings of your aircraft. That would reduce reinforced weapon mounts to carry cruise missiles and heavy turrets.
But i really have no idea why a fixed, flexible weapon mount can hold a light autocannon, but not an HMG...maybe they really forgot to write "reinforced"...."aren´t consistent" descripes it exactly.
Mike