I might be wrong but I think that a mistake was made while explaining the transition of beings from the lower realms to the Brahma realms on the destruction of the planet.
I would like to remember that the universe is something like infinite (or very big at least). There are innumerable clusters of 10.000 systems in which each and every system is passing through their own cycle. Considering this, beings that belong to any real, with the exception of those with subtle/non material bodies, will be reborn in another cluster in correspondence with their kamma at the time of the destruction of their planet.
This beings will only be “forcibly” reborn in the Brahmas realms with the Contraction of the entire universe, when there is no other place where their accumulated kamma can express its effects.