Hello Bietrume,
I did not notice any difference in the plates.
The magnet seems indeed strong, at least for it’s thickness, just ~ 0,8 mm.
I suggest to ask Mr. Schlumpf himself about your problem:
support[at]schlumpf.ch
(Please replace [at] with @)
Above new plates (and the drive) are not for myself, they will be sent to an American Strida fan.