Physical Inventory Adjustments
As you experience, physical inventory is a inventory counting and auditing activity which is quite laborious. Unlike Cycle counting, physical inventory needed to count all the inventory and corrections needed to be incorporated in the system. When the corrections are huge in number, manually doing these corrections in the System is quite difficult and not user friendly.
Option 1: Non Out-of-Box solution of using WebADI
One option could be developing WebADI templates to enable eased out entry of all corrections in Spread sheets and than loading to the Application. This still needs additional effort is developing the WebADI template as there is no seeded template to facilitate the Physical inventory adjustments.