Overall, if you just report the rental income/expenses on a 1065 partnership return, your life will be significantly easier and much simpler.
But if you want to report only your half on SCH E of your personal tax return, then do exactly that. Report *YOUR* half. Therefore, you claim 100% ownership and cut *everything* in half. So if the cost basis of the property is $10,000, your cost basis is $5000. If the rent received for the year is $12,000, your rent received is $6000.
When you elect to let the program "do the math" for you, the program can not do "all" the math. It's just not possible. Some if it you have to do yourself manually, no matter what. So to keep it simple,you might as well do all the math yourself, and just cut everything in half.
