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, Boruch She-Kivanta! Your question is asked by the Minchas Cohen, cited in the Hebrew Artscrolls note 27.
1) Minchas Cohen answers that there is a big difference between the Tnai of the Mishnah and between the Tnai of Rabbi Shimon. The Tnai of the Mishnah is simpler. The Tnai does not relate to what kind of minchah one is offering, but rather merely to the question of whether this is an obligatory mincha or a nedava.
2) In contrast, Rabbi 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 tnai 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 nedava. Now, every different combination of challos and rekikim represents a different korban, so here the Tnai 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 nedava". In this case, the Tnai is actually deciding whether the korban will be an Asham or not, not merely whether it is a chova or a nedava. Similarly, R. Shimon's tnai decides how many rekikim and how many challos are chova, so it changes the nature of this mincha, not merely whether it is a nedava or chova.
Yasher Koach
Dovid Bloom