Not quite Kronos, buying back the source gives them just that, the code, nit doesn't cancel the Hyperion's license to sell the OS, the contract wasn't terminated at the time, although it was some time ago.
The way I see the only way that Hyperion could ever recover their development cost would be trough the OS sales, but since Amiga has denied all the possibilities for that to happen is only natural that Hyperion themselves don't ease the source code transfer, of which Amiga Inc didn't even menage to fully pay it... be it 250$, 2500$, or whatever amount it may be.
