1)
What are the implications of "Lo Chein Nasan l'cha Hashem Elokecha"?
1.
Rashi and Targum Yonasan: It implies that Hashem gave you other sources from which to receive the necessary information - the Urim ve'Tumim via the Kohen Gadol and righteous Nevi'im.
2.
Seforno: The predictions that emerge from the above are unreliable when they apply to Yisrael. 1
1
Seforno: As the Gemara says in Shabbos, 156a, 'Ein Mazal le'Yisrael'.