What is the interpretive lesson of the textbook’s 100/150-dirham dower example?

Particles of Meaning: Waw, Fa, Thumma, Bal and Lakin

• The second approval always automatically cancels the initial rejection
• Simply saying lakin does not make an incoherent rejection and later approval a valid connected amendment
• The initial rejection always controls even if later speech is coherent
• The second amount is accepted without examining continuity