An Accountable Plan is when employees submit to the Employer for reimbursement of Business Expenses as provided in the IRS regulations. Then, the Corporation (employer) has an Actual Expense.

It might be something you should read up on, and counsel your clients, for 2021. I googled this for you:

irs accountable plan home office

Such as:

https://www.journalofaccountancy.com/issues/2020/feb/employee-expenses-accountable-plan.html

https://proconnect.intuit.com/taxprocenter/tax-law-and-news/how-your-s-corporation-clients-can-use-a...

https://proconnect.intuit.com/articles/home-office-deductions-expenses/