Bi-Level ceiling crack?

I have a Bi-Level house. They all get stress ceiling cracks, I've fixed mine several times, to no avail.

Finally I went into the attic, screwed 2x10's between the joists, screwed the ceiling sheetrock into the 2x10's, replastered, it lasted about 2 years, now it's back bigger than ever, any suggestion as to fix it for good ?