Thanks for thinking along.

Imho the mystery is not solved yet. The discussion in the posted thread is about the difference between the 804a and 806a. Obviously these have the same height (length), yet different mass. I would expect these magnets to be 1/2inch less long than the 802 otherwise they won't fit in their smaller housing. The guy who sold me the units sent me pics of 802 (old style in green, same length as my unit) and 806 and there is an obvious difference in length, hence magnet length.

The only thing I can think of is that the magnet of my units has the same length as a 802 but has the inner/outer diameters of the 804. Purpously or by accident. Tonight i will make a new weight measurement to be shure of the 2.5 kg. If my theory is correct it should actually be a little more than the 806 weight ( providing published data is correct).

I have unfortunately no gaussmeter to check the gap.