30 yr mortgage vs 15 yr mortgage

I am working on buying my first rental properties and have been crunching some numbers. I was looking at 15 yr mortgages on 4 properties valued at $90K. What I found when I looked at the profits vs a 30 yr mortgage was, that I would put an average of $2,200/yr more per property back in my pocket with a 30 yr mortgage. The total interest was about $40K with a 30 yr and about $17K with a 15 yr. Total profits drop on the 30 yr mortgage by about $26K. Am I crazy or does having the liquid capital make the 30 yr mortgage more appealing?