Did you hang the sheet rock on the garage ceiling and then blow in insulation from above?

No, the drywall went on the garage ceiling first. However, the drywallers left sheets of sheetrock off select spots, so the insulation crew could insulate. Then the insulation crew blew in the insulation from where the sheetrock was missing. They net the area with a fiberglass mesh where the drywall was missing to hold up the insulation. Lastly, the drywall crew came back and installed the missing pieces of sheetrock.