This is all somewhat settled law. It's the same rules as a home office deduction but with exceptions. They pay based on the square footage of your dedicated workspace compared to your home.
If you don't have a dedicated workspace, you can't take the home office deduction and your employer technically doesn't have to reimburse you anything (so this is more beneficial to wealthy people with dedicated home offices).
If you don't have a dedicated workspace, you can't take the home office deduction and your employer technically doesn't have to reimburse you anything (so this is more beneficial to wealthy people with dedicated home offices).