oops. I didnt account for a score <63. Here is the corrected formula
=IF(A1<63,A1,IF(A1>78,A1+75,IF(A1>70,A1+55,A1+35)))
I prefer lookup tables too, but I'm not always sure a poster will. It helps to know though that this aspect of scoring in Kismet has been the same for several decades...