[banryu79]

Yes and you should do this for each single "Randomize events.cfg" file you found in each single sub-mod (the folders inside the MODS folder).

Ok, let me explain with an example, let's consider the "Randomize events.cfg" inside "MODS/WB's Patrol Orders - North Atlantic/cfg"

First you edit this section:

;----------------------------------------------------------------------------------RANDOMISED INTRO MESSAGE
[0:data\Menu\en_menu.txt]
ApplyToPeriod=19390101|19450531
ChooseFrom=86
RndMidPat=1

0_STRINGS|13=SINK 'EM ALL! jimbuna
1_STRINGS|13=War does not determine who is right - only who is left
2_STRINGS|13=Releasing the atom has changed everything except our thinking...
3_STRINGS|13=There are no atheists in foxholes
...

Then you got this one:

;----------------------------------------------------------------------------------CHANGE PRE-SINKING MESSAGE
[1:data\Menu\en_menu.txt]
ApplyToPeriod=19390101|19450531
ChooseFrom=2
RndMidPat=1

0_STRINGS|4197=Message received.|Continue patrolling your allocated patrol grid until enemy ships engaged and sunk!|Good hunting.
1_STRINGS|4197=Message received.|BE MORE AGGRESSIVE!!!|Report again once you have destroyed enemy shipping!

And finally the relevant one:

;----------------------------------------------------------------------------------SECONDARY PATROL ORDERS (NORTH ATLANTIC - VII NORTH)
[2:data\Menu\en_menu.txt]
ApplyToPeriod=19390101|19450531
ChooseFrom=182
RndMidPat=1

0_STRINGS|4198=Good work! Patrol grid AN84 for 24 hours, if fuel and torpedoes permit, before returning to base.
1_STRINGS|4198=Good work! Continue patrol as current fuel and armament disposition allows. Good hunting.
2_STRINGS|4198=Good work! Continue patrolling your current grid for 24 hours, if fuel and torpedoes permit, before returning to base.
3_STRINGS|4198=Good work! Patrol grid AE81 for 24 hours, if fuel and torpedoes permit, before returning to base.
4_STRINGS|4198=Good work! Patrol grid AE82 for 24 hours, if fuel and torpedoes permit, before returning to base.
5_STRINGS|4198=Good work! Patrol grid AE83 for 24 hours, if fuel and torpedoes permit, before returning to base.
6_STRINGS|4198=Good work! Patrol grid AE84 for 24 hours, if fuel and torpedoes permit, before returning to base.
...

And you are good to go!

EDIT: I advise you to first of all disable the mod from SH3 Commander, then edit the files and finally re-enable it. It should work as you desired!
With the RndMidPat falg set to 1, each time you re-launch the game with SH3 Commander you get a new (random) secondary patrol grid that you can receive, in-game, sending a patrol report to BdU.
For game play immersion I only restric myself in doing this if I already sunk a ship in my current grid or spent more than 3 days patrolling it without founding nothing.