CSS- what?

So I am starting the CSS and printed out the worksheet to prep for it. It is for my son entering in Fall 2016 and I am estimating 2015 income etc. I am using the right form because they are asking for projected info for 2016.

On the worksheet directions they ask you to have at the ready the 2014 federal return, but they also ask for the 2013 return as well on the worksheet directions.

Unless I am missing something, I don’t see anywhere on the worksheet questions that they ask you to fill in any 2013 federal income tax info. Why would you need the 2013 return then?

Many colleges ask for 2 years back of tax returns when applying for aid before the latest return (2015) is done.