Not itemizing deductions. Do I enter mortgage interest for my home office by checking "Yes, include for this home office deduction" or as "excess mortgage interest"?

The instructions are unclear. Under "Excess mortgage interest" it says "If you have excess mortgage interest and it's included in the entire home mortgage interest reported for this home office, enter 0." Then it says "If you have a mortgage but are not itemizing deductions, enter your mortgage interest here." Which should I do?