Well... if we're going to go full nerd here...
Even though 10 minutes is our arbitrary system, it's a still a subdivision we arbitrary made toward a natural phenomenon which is the time it takes for earth to make 1 rotation around it self. So...
10 minutes = 1/6 of an hour, which an hour is 1/24 of a day; 10 min = 1/6 * 1/24 = 1/144 of a day
1 rotation = 360 degree per 1 day
1/144 of a day * 360 per day = 2.5 degree every 10 minute
So... maybe his Genjin nature has some interactions with earth magnetic field that the buildup will release every 2.5 degree of the earth's rotation?