Hi Holothurin
This objective in v2.4 was 80,000
The update from 2.4 to 2.5 was focused on removing the feeling of chasing tonnage target. Instead, all mission were changed to patrol area.
This one is the last one of TotalGermay and in truth is not meant to be passed. This was the first test of campaign ending by date (before the issues with Ubi and no tonnage recorded drama)
That objective is open for 5 or 6 months and can cover 5 to 10 patrols (depending on dock time settings), so I did not want users finishing this one too soon.
there are some rich pickings in this area - enjoy your patrols
Editing file probably won't cause any issues as the change will not take effect unless you restart your career.
You can edit your save files to :-
is objective complete=pass
or just re-dock a few time to pass time and allow time to end TotalGermany (CoastalWaters)
When you get to the wolfpack missions later in the war, you will again notice very high tonnage setting.
Here your fellow (AI) uboat kills will count towards your own totals and so is set high by design