[Front Runner]

I've done quite a bit of experimentation and I have verified there is a significant difference in the synchronization of the celestial sphere to the in-game clock. When playing at 1x from sunset to sunset from point A to point B, there is about a 1/4 hour difference when playing the same route and speed at 512x and/or 1028x. For example, at point B after 1x, sunset happens at 18:10; at point B after 512x sunset happens at 18:24. Over the course of several days at 1x there is a significant difference between the celestial sphere day/night cycle and the in-game clock time which can lead to being attacked by air in the middle of the night playing at 1x, while the in-game clock is indicating a day time cycle. I'm going north-south, not east-west in my testing.
Although this doesn't really apply to the FORTSU mod, it may help to explain some weird situations if a player has had the game running at 1x for long periods of time.
I have a few more experiments to perform but I am convinced there is a difference. SH4 is not meant to be played at 1x except when setting up an attack or defending from an attack.
Of course, one could just ignore the in-game clock all together and play at whatever game speed you wish.