Incursion Scarab of Timelines

Hi, I'm using the "Incursion Scarab of Timelines" curiously, when I use it on my map device and the incursion is reset to 12 incursions, it drops a Chronicle of Atzoatl with an Area Level of 37 (I'm farming T14+ maps) and when I use it when the incursion have 8 incursions remaining (doing the next map), it drops a Chronicle of Atzoatl with an Area Level of 64, only when I'm doing the third map (4 incursions remaining) that it drops the Chronicle of Atzoatl with an Area Level of 83, idk if it's a bug or if this is how it works.

Thanks for reading.