Cash on Cash % increase over time

[Justin Webber]

I like to finance for 15 year fixed with 25-30% down.  When considering Cash on Cash % at a 15 year note is much lower at first and increases over time compared to a 30 year.  My thought is to pay them off sooner to reap the benefit of greater cash flow later.  Does this make sense given my strategy?  Second question-  I posted the calculator on the prospective property in the other forum asking if student rental being a niche should I expect slighter lower %'s using the BP calculators.  Any advice would be greatly appreciated.

Thank you,

Justin