Sometimes the text is pshat (what animals are permissible to eat, whom one may marry or have relations with) but even then there are depths to the text which require learning to use the various “owner/operator manuals” you refer to. Obviously other parts (how to slaughter) absolutely require RTFM.
As for the contrarian interpretations, theres the Pirkei Avot about those disagreements begin “for the sake of Heaven”. I personally enjoy the contrast between Rashi & RAMBAN regarding the law of the captive war bride. Rashi looks at the potential consequences for the husband from a very pshat POV but RAMBAN is looking at the situation as much from the woman’s situational POV and how the whole thing can impact the new family & community. Here both are “right” but that doesnt change the text of Deuteronomy one bit.
Theres face value and then theres face value 
