Corrected entry: Mozzie's secret loft is called Tuesday, then when explaining it to Elizabeth, changes to Thursday.
By the Book - S2-E4
Corrected entry: While Peter is waiting for the elevator for lunch, which is occupied by Mozzy and Neal, the numbers on Peter's floor change from 20 to 18 to 21.
Correction: The numbers are changing because of the elevator. There Are two signs, one above the elevator - that shows what floor the elevator is on. And the other sign is on the right, that shows what floor you're standing on. So no, it's not a mistake - it confused me too at first.
Correction: Mozzie has a number of different hideouts, each with a different name. It also wouldn't be surprising for him to lie about the names of each to help keep his secrecy.