It's not that different really. Why could DH not have released the last 2 issues for the other two series between now and Dec.
If Dark Horse can sell the Trades for the other two series they should have finished releasing those issues first seen as they were 50% released. Especially if they can bang out a 5 issue series before then that started releasing after the Shutdown.
Based on that. It's the same to me. That's why I wouldn't put it past them.
Although....... I think I can agree that it is a bit Shadier to release 4 issues of the series, knowing that they would not finish it, to bump up trade sales.