Implied question: [The latter harvesting] is Gorer harvesting and grinding with it. This should be considered Greirah of Greirah!

Answer #1 (Rashi): [It is not considered Greirah of Greirah], for this that harvesting is Gorer harvesting is not considered Greirah, since it was in one Helam;

However, the corresponding grinding is considered Greirah, because the harvesting of Zadon Shabbos is not [directly] Gorer grinding of Shigegas Shabbos. It is Nigrar with it only through the harvesting with it. The Korban is primarily for [harvesting].

Answer #2 (Ri): [The first] harvesting is considered Greirah, for it says that harvesting is Gorer harvesting;

However, the grinding is not considered Greirah of Greirah, because he cannot atone for [the first] harvesting unless it atones for the grinding with it.

Implied question: Two k'Zeisim of Chelev in one Helam is not considered Greirah!

Answer: Even so, harvesting and harvesting is different, for one was Shigegas Shabbos and one was Zadon Shabbos;

The reason for the one who says below that harvesting and harvesting do not join is because he disagrees with the concept of Greirah.

Question (Rashba): According to this, we could find the argument of Abaye and Rava even with three acts of harvesting, e.g. he harvested amidst Shigegas Shabbos and Zadon Melachos, then harvested amidst Zadon Shabbos and Shigegas Melachos, and he found out about the first, and then harvested amidst Shigegas Shabbos and Zadon Melachos;

According to Rava, if he brought a Korban for the first, it atoned also for the second, but not for the third. According to Abaye, it atoned also for the third!

Observation: We could have said that the Mishnah is like R. Gamliel [who says that Yedi'ah after eating half a Shi'ur has no effect. It is a Chidush that they join], like we say below (71b).

Implied question: [R. Asi] could have answered even to discuss the Reisha, e.g. he ate in two plates, and it teaches unlike R. Yehoshua, who holds that plates divide even to be lenient!

Answer: He prefers to establish it like R. Yehoshua.

Implied question: Regarding lashes, they join, like we say in Avodah Zarah (66a) and Me'ilah (17b)!

Answer: Regarding Korban, it is obvious to [the Makshan] that they do not join.

Implied question: Above, why didn't we ask "[if Reish Lakish discusses the Reisha,] this implies that the Seifa discusses two species and two plates. Is there any need to say [that he is exempt]?!"

Answer: [The Gemara] was not concerned to elaborate [and ask this], since we do not conclude like this. (The entire Mishnah does not truly discuss two species at all.)

Explanation (Rashi): R. Akiva and R. Tarfon argue about this in Kerisus (22b. R. Akiva says that one brings Asham Taluy for Safek Me'ilah, and Asham Vadai when he finds out that he sinned. R. Tarfon says, he brings the money, Chomesh and an Asham and stipulates. If he truly transgressed, it is Asham Me'ilah, even though he did not find out yet.)

Rebuttal: This is wrong. The Mishnah there says that R. Akiva says that he brings two Ashamos only for a large Me'ilah. It is better that he bring two Ashamos, than to bring one Asham and stipulate that if he will not find out [whether or not he transgressed, the value of] his Me'ilah is Nedavah (a gift to Hekdesh);

However, regarding a small Me'ilah, R. Akiva agrees that he brings one Asham and stipulates. It is better for him to give a small Me'ilah [to Hekdesh] amidst Safek, than to bring two Ashamos;

The Gemara says that we learn from both of them that Asham Vadai does not require Yedi'ah beforehand. (Hagahos ha'Gra - R. Yosi holds that Asham Vadai requires Yedi'ah beforehand - Kerisus 7b.)

Question: R. Tarfon says "why does he bring two Ashamos?" This connotes that he teaches good counsel!

Just the contrary! Since they argue about a big Me'ilah, it is better that he bring two Ashamos, like R. Akiva said, than to bring one Asham and the Me'ilah and stipulate, like I explained!

Answer: R. Tarfon does not give good [monetary] counsel. Rather, the sinner does not abandon Aveirah (not now, and perhaps never) through bringing two Ashamos (i.e. Asham Taluy now, and Asham Vadai when he will find out). Rather, he brings an Asham and his Me'ilah, and stipulates.

Question: According to R. Akiva, why does he bring two Ashamos for a big Me'ilah, and an Asham and the Me'ilah for a small Me'ilah? He should always bring one Asham and stipulate, and when he will find out [that he sinned], then he will bring his Me'ilah!

Answer: [He cannot,] because it was taught that one who brings his Asham before bringing his Me'ilah, he was not Yotzei.