What is meant by the Venerable Mahasi Sayadaw in regards to "The Attainment of Fruition"?

In The Progress of Insight by the Venerable Mahasi Sayadaw , in the section The Attainment of Fruition, it is said that: > This occurs in precisely the same way as the path and fruition consciousness that occurred earlier in the consciousness-sequence belonging to the initial attainment of the first path. The only difference here is the capacity of the fruition attainment to last long. Whereas, in A Manual of Abhidhamma by Narada Maha Thera it is said that: > Each of the four Supramundane Paths arises only once in the course of one’s life. Is Mahasi Sayadaw taking a differing position than what is said in the Abhidhamma or am I not understanding him correctly?