Why does the Gemara say that even according to r' Shimon the mishna is good because he holds Maisi u'Masni. it would seem that our mishna itself that says to bring 5 types of menachos also has to agree to the Tnai that one would be his neder and the other 4 a nedava?
In other words, my question is that even without the problem of Minchah Ma'afeh we would still have to say that a Tnai would work...?
Thanks
Yanky
Yanky, Baruch she'Kivanta! Your question is asked by the Minchas Cohen, cited in the Hebrew Artscroll edition, note 27.
1) The Minchas Cohen answers that there is a big difference between the Tenai of the Mishnah and the Tenai of Rebbi Shimon. The Tenai of the Mishnah is simpler. The Tenai does not relate to what kind of Minchah one is offering, but rather merely to the question of whether this is an obligatory Minchah or a Nedavah.
2) In contrast, Rebbi Shimon discusses someone who made a Neder to bring a combination of Challos and Rekikim but he can no longer remember how many of each. He makes a Tenai that "however many Challos I was Noder will be Challos, and however many Rekikim I was Noder will be Rekikim, and the remainder will be Nedavah." Now, every different combination of Challos and Rekikim represents a different Korban, so here the Tenai that he makes is creating a new Korban.
3) This is why the Gemara cites a Beraisa where one says, "If this person is a Metzora then this animal will be an Asham, but if he is not a Metzora then this animal will be a Nedavah." In this case, the Tenai is actually deciding whether the Korban will be an Asham or not, not merely whether it is a Chovah or a Nedavah. Similarly, Rebbi Shimon's Tenai decides how many Rekikim and how many Challos are Chovah, so it changes the nature of this Minchah, and it is not merely determining whether it is a Nedava or Chovah.
Yasher Ko'ach,
Dovid Bloom