Odd (but welcome) sinking credit

[desirableroasted]

This was odd....just how far away can you be from a ship you hit for SH3/GWX to record a sinking? How about 14 hours and more than 150 km...

I'm coming home on fumes through BF41, April 41, when I get word of a convoy. I whack it around 2030... sink a large merch and a large cargo, get one hit on a pyro and one hit on someone behind her (had my spread angle a little too wide). Glad for that much, given the crap weather.

I break off, hit them again at 0130, hoping to kill the pyro and whoever else I wounded. It's still foggy and I'm one row further in than I thought, so I end up snapshooting a whale ship (bow tubes), which goes down and a large merchant (stern), impact but no sink. No sight of my two wounded.

Ok, not good, but a nice cap on a good patrol. I'm down to 2 stern fish and running dry, so I break for home. Captain's log underway shows the three sinks.

Yet... when I get home, I've got mucho extra tonnage. A pyro went down about 45 mins after the 2nd attack... OK, could be that I was still in hydro range, but got no notice. But a large merchant went down 14 hours later in BF39, when I would have been 150+ km away...

I'm not complaining. I've been shortsheeted so often on kills that this is nice payback. But what's the algorithm for this stuff?