In every place that R. Gamliel agreed with Admon, the law is as Admon; in all other places, not. It dosen't include the first case - we said formerly that in this case:" if the estate is small, the daughters are fed and the sons beg for their food; Admon: Because I am a male, I lose?!"Actually the sons will beg for their food (which equals the daughter status to the widow)
Rafi Magid
TOSFOS on 108b (DH Admon) asks your question. Tosfos answers that Admon is not actually arguing in that Mishnah. He is merely asking a question (i.e. wondering aloud), and Raban Gamliel agrees to his question. The Halachah, though, remains like the Chachamim.
D. Zupnik