When Oscar hands Kevin the iTunes gift card he states there's $7 left on it, but this isn't how iTunes gift cards work as the entire balance needs to be redeemed to an account.
When Andy is waiting in line to audition, he tells Casey he is listening to his starting pitch, "A440" (Hz) on his earbuds. You can hear the earbuds playing the correct pitch of A440 but Andy sings it down the octave, which would make his actual starting note A220.
Andy sings the Cornell Alma Mater ("far above Cayuga's waters") for his audition, but misidentifies it as the Cornell Fight Song (usually "give me regards to Davy"). Andy would be unlikely to make that mistake.