Please forgive me if I should already know this… Are the songs for prescreens supposed to be the same or different that the ones for actual auditions?
TIA!!
Each college audition requirements are different. Check with each school.
What Ducky said^. Some are required to be the same and some schools don’t care. Check with each school.
Of course, if the school gives specific instructions, follow those… but if not, I would say stick with the songs you’ve already done for prescreens, unless you’ve found some mindblowing new song in the time between your prescreen and your audition!
Whatever you sing, make sure you have additional choices in your book. You may be asked to sing something else & you need to be ready for that possibility.
So much time passed between my kid’s few prescreens, and the actual auditions, a great deal of the material had changed. Do what you feel most comfortable with!
In addition to having other songs in their book, it is also important that they are prepared to sing the entire song, not just the cuts. My daughter was asked to sing an extra song more than once, and she was also asked to sing an entire song in a couple of auditions.
Good point @Onourown. Your post triggered a memory for me… at an audition at Unifieds, my kid was asked to sing a song from a role and show that was listed on the resume!
^^^my S, too. Luckily, it was a fairly recent role so fresh in his mind! A good reminder never to embellish the resume 
D had the song question once… but at another audition, she was asked to do something from a play she had been in - which seemed far more complicated to her. It was not as if someone said "Oh, I see you played Juliet, could you do the balcony monologue… she had been in Picnic by William Inge, and they wanted her to do something in that character. Kind of threw her - but she rallied and came through (accepted to the school that asked too). I guess the take away is that anything on the resume is fair game
So my kid sang Giants In The Sky at 15, and the musical is on his resume. But his voice is deeper now and he cant easily reach those notes at this stage. Mercy. Guess he better sharpen his falsetto skills!? 
It would be a very rare occurrence that a student would be asked to sing something on their resume that is not in their rep book from a role that goes back several years. However, its not a bad idea to have one or two songs in your rep book from your most recent role(s).
Rare for sure, but the song my kid was asked to sing was not in the rep book, and the accompanist played it from memory! I don’t feel like it was a “gotcha” situation at all, just the sense that they wanted to see something from the resume. I can’t recall if their were questions asked regarding how recent the role was played.