Timing is everything (#SFWApro)

While I haven’t reviewed them yet, I have added Killing Ground and The Warning to my Hellboy chronology. And in placing them in 2006, I’m reminded of how tough establishing a timeline can be.
Pretty much every timeline I looked at places Hellboy: Darkness Calls in 2006, before Killing Ground. The Hellboy Companion, however, sets it very definitely in 2007. Which means it also comes after The Warning, as that’s only a week after Killing Ground.
So what about The Black Goddess, which is next in the BPRD? A cursory look indicates it takes place fairly soon after The Warning, which would put it, too, ahead of Darkness Calls? But am I misreading it and there’s actually more time between the two BPRD tales?
Not that this is of cosmic import, but when I enter things in my own timeline, I want them right.