Hi @dingyuan1991 ,
Yes this is indeed why I am worried that your direct comparison between the two cases will not work. Please note, as explained in the manual entry for USRBIN and exemplified in this post that “The results from USRBIN are normalised per unit volume and per unit primary weight, except region binnings and special user-defined binnings, which are normalised per unit primary weight only,”. I don’t see you applying the correct normalisation in the flair file for the case where you use region binning.
Hope this puts you in the right direction,
Cheers,
Andreas