Why is deductible interest form 1098 not reduced by amounts in business use of the home?

[CherylW]

If you used part of your home for business that produces taxable income, then the interest should be prorated.  

Depending on what kind of business you had, you can take a deduction either on Schedule C or E.

When it's entered in your C or E input, Turbo Tax asks you about usage.