There is a teacher who says that the mukhaarij for raa is when the tip and bottom of the tongue touches the gums of the front four teeth

Question
Assalaamu alaykum
There is a teacher who says that the mukhaarij for raa is when the tip and bottom of the tongue touches the gums of the front four teeth and  noon is when tip of tongue when it touches the gums of the top six teeth. This is obviously wrong but is it because they are teaching another riwaayah as I have heard that in another riwaayahs the mukhaarij differs.  I don’t recite in this way but if I caught someone explaining mukhaarij in this way would I class this as a major or minor error in the recitation of Hafs?
JazakAllahu Khayran for all your help and support.

Answer
Wa alaikum assalaam wa rahmatullahi wa barakaatuh.
The makhaarij (or articulation points) do not differ from one riwaayah to another, or from one qiraa'ah to another.  Imam Ash-Shatibiyy in his poem on the seven qira'aat has a section on the articulation points and he does not differentiate between one qiraa'ah and another in this section and certainly, this would be a source for that if there were any differences.  The same holds for Imam Ibn Al-Jazaree in his poem Tayyibatu-n-Nashr on the 10 qira'aat with all their turuq.  He describes the articulation points exactly like he does in his poem on basic tajweed. 
If the sound resulting from the incorrect articulation changes the sound so much that it becomes a different letter, then it would be a major mistake. 
Wa iyyaakum.