I received 2nd MR & Invitation to pre-arrival letter, what’s the chance of getting PR? Pls advise

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i’m aug 2016 applicant.
AOR: dec 2016
1st MR: dec 2016 (passed in Jan 2017)
interview: may 2018
additional doc requested: may 2018
2nd MR & pre-arrival letter: 2 days ago