Assuming that we have F!Robin's stats at -1 Atk over M!Robin (because of weapon differences in Mt), we have 5* Lv40 F!Robin with   #*  HP   AT   DF   SP   RS 5*  40    39    29    29    22 4*  38    33    27    27    20  3*  36    31    25    25    19 Which is super middling, but considering her tome is effective against Olwen and Reinhardt (doubling them automatically) and effective against Sully/Jagen...what do we have? You're looking at what I believe is a raw 80% boost