Shnei Kesuvim Hamachishim Zeh es Zeh

In the previous post we mentioned an excellent shiur from Rav Hershel Schachter (here) where he discusses earning a living in halacha. In the course of this shiur he mentions the well-known gemara in Berachos 35b that has a machlokes between Rabbi Yishmael and Rav Shimon Bar Yochai in terms of how to reconcile the pasuk of v'asafta d'ganecha (implying one should work to earn a living) with the pasuk of lo yamush sefer hatorah hazeh (implying one should always be learning torah).

Rav Shimon Bar Yochai says that the answer to the contradiction is that when klal yisroel is doing the will of Hashem there work is done by others. Otherwise, they have to work for themselves. Rav Yishmael says that derech eretz and learning should work together hand in hand.

So whom do we pasken like?

It is pretty clear that we pasken like Rav Yishmael. However, Rav Schachter brings what seems to be a totally novel reason as to why this is.
He explains that there is a general rule of shnei kesuvim hamachishim zeh es zeh, that if you have two pesukim that contradict one another, so we use the pasuk hashlishi, a third pasuk, to answer the contradiction.

What do we do if we have no third pasuk?

Rav Schachter explains that in such a case it is a machlokes between Rav Eliezer and Rav Yehoshua in Pesachim 68b. There the issue is that one pasuk implies Yom Tov is "kulo lashem" and the other implies it is "kulo lachem". Rav Yehoshua says that it's therefore either/or whereas Rav Eliezer says that we "kvetch" a pshat that it is chatzi lachem and chatzi lashem. We pasken like Rav Eliezer. Rav Schachter explains that from here we see a yesod that if we have two pesukim that contradict each other with no third pasuk we are supposed to "kvetch" a pshat. That is exactly what Rav Yishmael is doing in Berachos! Therefore, the halacha is like Rav Yishmael!

This explanation seems to be a huge chiddush, does it have any sources anywhere?