When gaining xp from sepulchre, you get the xp on the current floor then you go to the next floor or lobby. Jagex has also added small amounts of xp per floor to obstacles that aren't reflected in the large xp drop at the end of a floor. On top of that, you can go to next floors in multiple locations as well as receive xp in multiple locations.
It seemed more intuitive to sum the xp as it's received vs tracking every region.
When gaining xp from sepulchre, you get the xp on the current floor then you go to the next floor or lobby. Jagex has also added small amounts of xp per floor to obstacles that aren't reflected in the large xp drop at the end of a floor. On top of that, you can go to next floors in multiple locations as well as receive xp in multiple locations.
It seemed more intuitive to sum the xp as it's received vs tracking every region.