that’s what I have been thinking, although that would push it above 4 hours.
If this is the case, it could be possible that using the change vetex made to bounty npcs (so that they drop charts regardless of if they are your rival) to just stock up on charts before charting. It would be a boring answer though.
I have decided that the only way to figure this out is to send a spy account after you. You should watch your back when doing treasure charts for the next 5 days.
Goodluck with that ngl, I pretty much only play games whenever I have free time from college. At best I can be semi-active in any social platforms like the forums.