Sure...but there should be a line in there somewhere.
While you may have more than one company of Astartes, I doubt many folks will be fielding it. Seriously...124 Space Marine Models is a lot on one table (but I reckon if you bring multiple companies, multiple Iron Halos would be reasonable).
I figure as long as folks stay within the bounds of reason all is well.
No...there is no Force Org Charts. That doesn't mean field an army of Chaplains, or Hive Tyrants, or Baneblades, whathaveya...
The idea is to stay within the Spirit of the Rules, especially when the rules are vague. In this case the rules are specifically vague to discourage folks from min-maxing and abusing rulesets (which often happens with rules that are designed to be inclusive and complete...such as the Warhammer 40,000 Main Rule Book.)
Apocalypse is driving towards a far more liberal, loosey-goosey, "fun" style of play, geared towards non-competitive play.
Doesn't mean there are NO rules, just that the onus is on us all to create our own levels of what is considered "reasonable".