Residential rental income is passive income and the bottom line is the same when you list in Turbotax a multiple unit complex as a single entry.
If you list as separate units with different address you must prorate total cost and [land value land is not depreciated] to each individual unit.
It depends on your individual intense attention to keeping track of the each individual unit rent history. Record keeping and allocation of cost is more detailed.
Personally each unit in a complex is listed as a single unit with addresses 132-A, 123-B,123-C,123-B etc.[Calculate the percentage of cost to each unit and use that same percentage as long as you own the property] You have to be consist on current and future tax returns.
You cannot deduct any loss of rental income for the period the property is vacant.
Idle Property
Continue to claim a deduction for depreciation on property used in your rental activity even if it is temporarily idle (not in use). For example, if you must make repairs after a tenant moves out, you still depreciate the rental property during the time it is not available for rent.
Publication 527(2016), Residential Rental Property
http://www.irs.gov/publications/p527/ch01.html#en_US_2016_publink1000219000
Good luck on being a landlord!
