Looking at the whole process of a typical working day, the only time you need to enter 'Manage' is to adjust inventory. Be it purchases, or stock adjustment for wastage, etc.
Would it make more sense to have Inventory Transactions & End Of Day Records available in the Warehouses screen, or atleast have a button to add an Inventory Transaction record and to add/edit an End Of Day Record.
It would eliminate the need to access Manage->Inventory, but on the down side there would need to be a Role Permission added for 'Inventory Adjustment' so normal staff can search through inventory, but not adjust inventory.