Imperial Fists legion organisation 2 - more things nobody cares about

I was reading Lexicanum, and found the exact thing that had been frustrating me with how the Imperial Fists organised their legion during the Great Crusade and Horus Heresy. It seems I was right, that company-level captains are pretty much the highest rank of officer, and that (likely) the only numbered formations are the companies and the echelons within them. Battalions and Regiments were pretty much just a collection of companies rather than rigid like with other legions (namely Ultramarines and Word Bearers) - also it seems that instead of regiments, their "chapters" were Crusades or Households, seemingly depending on whether they were assigned to offensive or defensive roles, headed by Lords Castellan (defensive Households) or Lords Seneschal (offensive Crusades).

I feel relieved to know this information. I wasn't expecting to feel that way, but apparently this has been bugging me a lot more than I was aware.