Ok, thanks everyone, I guess everything works as it should then.
I'm certain though that a couple of weeks ago time used to advance properly whenever I finished a patrol (in base after patrol 1, Jan 15th, in base before patrol 2, Feb 4th, and so on). And I still can't figure out what changed that.
Does SH3 Commander take the time spent in base into account when deciding what files to load based on date? For example, if the game shows Jan 15th as the date in base before patrol (same as the end date of the last patrol), but the real date when the patrol is loaded is Feb 4th, will Commander load the files for January or February?