I've created a
little SH3 Commander mod which applies the info Marcello and La vache have posted in the thread. On the relevant date it will update the default torpedo loadout to reflect the two orders that they found, plus it removes three torpedoes from the XXI in order to allow for servicing.
The file replaces your basic.cfg so I only recommend it for GWX users as that's the base file I used.
If anyone has any more info it'd be great to see it...