They may think that using up MLRS rockets to lob the FAB-250s is a good stopgap measure, but to me the most interesting question is why they need to do that.
Why does it mean they’ve run out? Maybe, just maybe, the same genius who figured out how to turn them into cruise missiles said, what if again? Maybe, just maybe, he then said we can use these millions of old “worthless” Soviet bombs to supplement our vast stores of 300mm rockets and use that production line for some other kind of ordinance. If an engineer at Raytheon came up with the same kind of brilliant, cost saving ideas, he’d be fired and blackballed from the MIC on the spot.