Pip award end dates and how payment works?

Hi everyone, am I correct in my thinking that when your given a set pip award at tribunal, your pip ends on that day, even if you are currently waiting for a decision?
I was awarded pip at tribunal in April 2017 backdated from September 12th 2016 when my transfer from dla to pip was unsuccessful, and I was given a 3 year award 12th September 2016 - 11th September 2019, June this year I received the letter to let me know it was ending and that it was time to reapply and I got my form back to them 15th July, and was then given an assessment on the 12th August, as it stands now I'm currently waiting for my decision, I had what I believe to be my last full payment of pip on the 2nd of September, but I've not received a letter explaining what happens next as I think there will be just over a weeks payment owning me unless I am refused, I'm not sure if I'm right about this and would appreciate some advice, thanks in advance.

Thank you Gordon, I thought it did end on the date given, fingers crossed for a decision soon, I've not plucked up the courage to ring them for the assessment report yet.

Thank you Gary, as soon as my decision comes through I will ring for the assessment report, I'm to scared to while I'm waiting just incase I can work out its not good news, part of me wants to see the report and the other part doesn't, that's why I've put off asking for it.