The concept of Lo B'Shamyim Hi (It is not in heaven) is a central tenet to the Halakhic process amongst Rabbinic Jews and is summarized nicely by this Wikipedia Article:
The phrase "not in Heaven" is understood to justify man's authority to interpret the Torah. The Talmud explains "[The Torah] is not in Heaven" to mean that the meaning of the Torah itself is to be uncovered not by prophets, or even God's miracles or words, but by man's interpretation and decision-making. In the story of the Oven of Akhnai, "Rabbi Yehoshua affirmed the independence of man's interpretation from divine intervention since this is what God wills. In support he adduces the biblical statement that the Torah is 'not in heaven' (Deuteronomy 30:12)."
In the academic study of Jewish law, the verse "not in Heaven" serves as the Biblical grounding for the jurisprudential structure of halakhah (Jewish law). The source for Rabbinic authority is really from Deuteronomy 17:11 (According to the law which they shall teach you, and according to the judgment which they shall tell you, you shall do). As one author explains, thanks to the midrashic reading of the verse, "...God himself acquiesced in His exclusion from the halakhic process. Having revealed His will in Sinai in the grundnorm, He Himself, according to the Rabbinic explanation, entrusted the interpretation of His will to the Sages."
But my question is when did Lo B'Shamayim Hi come into effect? For example there are many laws given in the Torah that don't take effect until the Israelites are in the land of Israel. In the case of Lo B'Shamayim Hi we see Moses not applying this concept in several important instances. In at least 2 instances a situation arises in which Moses is unable to render a decision, the judges/princes/leaders are unable to render a decision, and apparently no attempt to arrive at a decision by majority happens. Instead Moses goes to God to get these halakhic matters resolved like in the case of Zelphehad's daughters.
The daughters of Zelophehad son of Hepher, the son of Gilead, the son of Makir, the son of Manasseh, belonged to the clans of Manasseh son of Joseph. The names of the daughters were Mahlah, Noah, Hoglah, Milkah and Tirzah. They came forward 2 and stood before Moses, Eleazar the priest, the leaders and the whole assembly at the entrance to the tent of meeting and said, 3 “Our father died in the wilderness. He was not among Korah’s followers, who banded together against the Lord, but he died for his own sin and left no sons. 4 Why should our father’s name disappear from his clan because he had no son? Give us property among our father’s relatives.”
5 So Moses brought their case before the Lord, 6 and the Lord said to him, 7 “What Zelophehad’s daughters are saying is right. You must certainly give them property as an inheritance among their father’s relatives and give their father’s inheritance to them.
8 “Say to the Israelites, ‘If a man dies and leaves no son, give his inheritance to his daughter. 9 If he has no daughter, give his inheritance to his brothers. 10 If he has no brothers, give his inheritance to his father’s brothers. 11 If his father had no brothers, give his inheritance to the nearest relative in his clan, that he may possess it. This is to have the force of law for the Israelites, as the Lord commanded Moses.’”
So my question is, when did Lo B'Shamayim Hi come into effect? Was it at the appointing of the judges, and if so, why don't we have instances of it being utilized and instead have only the opposite? Or perhaps it happens after the death of Moshe? But even that seems problematic as clearly the Umim and the Thumim were used to try and divine decisions.
So when was the concept of Lo B'SHamayim Hi supposed to be put into effect?