One of my clients took a home office deduction on form 8829, which flowed over to schedule C as expected. But now, after being question by the IRS the same home office deduction also flowed over to his schedule A increasing his home mortgage interest which only shows up on the filed tax return as one number on line 10 of the Sch. A. 

To me, it don't seem correct because it's flowing to the sch. C reducing taxable income and flowing to the sch. A increasing itemized deductions, aka double dipping.

Signed: Please Help.