Incorrect depreciation?

We converted our primary residence to a rental this year and it seems like TurboTax is calculating depreciation differently than I have read it should.

Our cost basis at purchase (minus land price) is 147,979,  so using straight line depreciation at 27.5 years I calculate that depreciation should be 5,381 dollars per year.  Since we put it into service June 15th for 54% business use it should be 2,905 dollars of depreciation this year,  but TT suggests 1,586.  Any idea why?