>> ~~~~~~~~~~~~~~
>> 200 Interstellar exploration and expansion begins
>> 380 Fenris settled
>> 390 Chartered Fenris Compay goes bankrupt, most colonists evacuated
>> 480 /Four-Day Planet/
>> 526 /Uller Uprising/
>> ~~~~~~~~~~~~~~

We know that HBP kept detailed notes and timelines.

As someone who has done this sort of thing in RPG world building,  this
sort of large world building is a living creature and it grows and
changes as you go.

So we don't know how complete or details the THFH were in 1952 versus
1962,  Nor how things changed, adjusted and moved around as HBP's view
on the matter evolved and changed.

The THFH is not received scripture,  divinely inspired and inerrant,
it's a work of art, which is organic, lives and grows.

(I can't tell you how many times I have discussed just this idea in
regards to Star Trek or Star Wars)

Don't get too hung up on where the details don't fit exactly.

I mean sure,  the fiddly bits are fun.

But if things don't fit together precisely, that's because it was a
slightly different HBP building in across his writing career.