Hi, i've got a doubt about the application of the principle of minimal flavour violation (MFV) in order to build extension of the standard model. https://arxiv.org/pdf/1603.08002v2.pdf In this paper at page 18 defines the MFV: "One very convenient approach to deal with this is to impose that new physics either respect the SM flavor symmetry or the breaking of it is associated with the quark Yukawa matrices." Then, at page 20 he applies it and it says that it imposes the couplings to be proportional tu the yukawas couplings. On the other hand at page 27 he uses the same principle, but this time the couplings needs to be all equal. Why is that?