That dating very much depends on what model you use. If you believe creationist, the Earth's magnetic field is declining, following an exponential decay. If they are right, the dating will be very different to the above, which assumes a mainstream science view of magnetic field fluctuation.
See here for a recent CARM discussion on the two different models:
The Earth's magnetic field is declining. Measurements have been made of the Earth's magnetic field more or less continuously since about 1840. Some measurements even go back to the 1500s, for example at Greenwich in London. If we look at the trend in the strength of the magnetic field over this...
forums.carm.org
There is more on the science here by the way:
Also of interest is that their data works in tandem with radiometric dating, further confirming that as a valid dating technique. From the above link:
As demonstrated above, the new 586 BCE chronological marker can help constrain the chronology of previous and future archaeomagnetic data from the same period and help validate suggested links between the Babylonian 586 BCE campaign and destruction layers in other sites. In this period, which is in the middle of the Hallstatt Plateau [33], dating using radiocarbon is very limited in its precision, due to the flat nature of the calibration curve. Therefore, archaeomagnetic dating using the new results as a chronological benchmark has a great advantage as a dating tool in this period. It can be used both for archaeomagnetic dating of other destruction layers and other finds that have not been dated historically and for the research of the enigmatic behavior of the ancient magnetic field in this period and region.
It will be interesting to see if creationists want to declare this as evidence that the Bible is true, given that doing so would be tacitly admitting scientific dating methods are valid.