I just published a new post “Nirōdha Samāpatti, Phala Samāpatti, Jhāna, and Jhāna Samāpatti“, that would hopefully address your question.
This post should cover the questions raised in the discussion forum under the topics:” Nirōdha Samāpatti”, “Difference between “Arahant phala samāpatti” and “Nirōdha samāpatti” ?”, and “Nirōdha Samāpatti and Amoha”.
If there are more questions on this and related issues, please ask them under the topic “Difference between “Arahant phala samāpatti” and “Nirōdha samāpatti” ?”. I am going to close the other two topics, in order to not have too many parallel and related discussions.