# Why does the $\mu^{+}\pi^{0}$ mode in flipped SU(5) becomes more important when compared to simple SU(5)?

I know that the higgs sector of these theories are different and all that. But what is the simple reason of why $p\rightarrow\mu^{+}\pi^{0}$ becomes comparable to $e^{+}\pi^{0}$? One thing I can image is some anti-symmetric tensor over generation number such that $\mu$ is preferred. But I do not know if that is the case.