...hang on... Maybe I'm being a bit thick here but what your posts suggest is that as a box-fresh C0 class drone: the mini 5 pro is limited to 400' altitude unless registered with DJI as a >250grm C1 class drone which increases its ceiling to...
Interesting... I'm reminded of the geo zone map function that started out the same way: optional and for reference only to begin with, then at the press of a button in DJI H.Q: became mandatory.
This may tie in with the (near) future requirement...