No. You are mistaken, both as to what really gets stored, and why you see it as different from what you expected. If you reread the paragraphs above, and consider how this relates to how you inspected the timestamps (uLE vs Sony Browser) and to the difference between your set timezone and that of Japan, I'm sure it will make better sense to you.
But, when i Start a game with uLE and do the same, saving a game at 18:47(Real time)... the game save show 23:47 (but the PS2 has 18:47) some like the GMT setings or similar thing was wrong...
This is a different aspect of the same thing again. The internal realtime clock is always set with such an offset from the time you enter in setting it, that it will be running on japanese time without DST offset. So if most homebrews show time/timestamps as 5 hours later than you expect, this means that you are either in a timezone -5 relative to Japan without DST active, or that you are in a timezone -6 relative to japan with DST active in your settings.
another case happend with the clock displayed by SMS, its show 5 Hrs. more from the Real time and the time set on the PS2, same of above example... :crazy: