<sigh> I'm going to be "that guy"...
Slow morning at work, was flipping through the final versions of the BFG:R Chaos & Space Marines lists (something I should have done when we were editing earlier), and realized that the VBB entry describes thunderhawk upgrades as "halve launch bays, rounding up," and the CSM thunderhawk upgrades are listed as "halve launch bays, rounding down." Now, there's only 2-3 ships where this even matters (Styx (specifically used as an example in the VBB entry), Retaliator, Exorcist), so I guess my question is, is this an issue?
I know that as a Chaos player I'd want to get 4 squadrons instead of 2 out of a 6 hangar bay CG, but taking CSMs does also open up the possibility of Marking a ship too, so the value of those +35 points isn't exactly 1:1 between the two lists. I also don't have my Armada book in front of me, and I don't remember if the original language for Chaos thunderhawks was "rounding down" either.
On the one hand it's differing applications of (nearly) the same rule, on the other hand, it's easily rationalized by "CSMs have been fighting the Long War in some cases for millennia... stuff breaks down, shortages are common, it's extremely difficult to keep things at full strength."