If I have a business loss and choose the simplified home office method, is there any benefit to still entering mortgage interest, prop taxes, home repair costs, etc?

[PatriciaV]

Your unused Home Office Deduction will carry forward to next year, where you can use it to offset any business income.

Comparing actual expenses to the Simplified Method may be worth the effort, if you have more than $1,500 in allocated expenses (the max for simplified). 

You can do this in TurboTax or you can do it yourself. Figure out the percentage of your home that is used for your office, total the home office expenses you have to report, then multiply the two. If the result is less than the square footage x $5, then you're better off taking the Simplified Method. Otherwise, enter your actual expenses.