Business & farm

Thanks.  Some functional questions...

- With a personal car used for business purposes, would I split the mileage based on our interest even though she did not do any actual business driving?

 

- In regards to deductions like mortgage interest as it relates to the home office.  It asks me to put in the amount from the 1098.  Would I split that?  It feels odd to do so because it is a specific number from an official document. 

      - On a related note, I assume I'd manually split points paid on a refi?