I know that's the case for Spharai vs Revenant Fists +2. If I remember correctly, RF+2 is somewhere like 5-10% better.
Edit: Just checked on Kinematic's spreadsheet, using the default gear/atmas(RR,GH,Apoc) of the spreadsheet and only changing WS and weapon, level 90 Spharai score 269.641 while Revenant Fists +2 score 297.302. Which is about 10.3% better. And to throw it all out there, the 90 Verethagna are 321.868, the 85 Verethagna are 308.525, and Revenant Fists +1 are 289.707.