Whilst it is true that the intensity of some of the archaeomagnetic levels used as anchors does not conclusively invalidate the dating offered by the Watch Tower Society, the dating for Beth-Shean does. The study says that event occurred around 900 BCE, but that would be 968 in Watch Tower Society chronology. Note that the levels that would be required for the Watch Tower Society's reckoning of the Tevet VII, Rehov V and Beth-Shean events fall well outside the higher band (yellowish shading) of the archaeomagnetic levels at that time.
900 BCE is the latest
date given for the "70-100" years before 830 offered by the study for the destruction of Beth-Shean, which it says was destroyed during the reign of Shoshenq (ruled 943-922 BCE). According to WTS chronology, Shoshenq reigned around 1011-990 BCE, and Insight
(volume 1, page 304) says Beth-Shean was destroyed in 993 BCE - for which the archaeomagnetic intensity levels are even more wrong.