PIP Tribunal award length

Hi, Hope someone can shed some light as to what might happen regarding reassessment/Review .
Background, Adult Son with Autism and ADHD applied for PIP sept 2016
Assessor awarded 9 points daily living
Feb 2017 Decision letter arrives DM awards 3 points no award
March 2017 Mandatory reconsideration New DM awards 7 points no award.
I become My Sons Representative and apply to Appeal
October 2017 First tier tribunal Awards 6 points.
I found several errors of law and was not happy about how they came to the decision
December Granted leave to appeal to Upper Tribunal
May 2018 Upper Tribunal agree there have been 3 errors of law and also makes notes about How the Ftt came to their decision ignoring medical evidence
Upper Tribunal direct for a New First tier tribunal to rehear the case giving directions where the first tribunal err'd
Today April 11th 2019 132 weeks from first application after 3 hours!! with one short comfort break, Son is awarded Standard Care and Standard Mobility
But the award is only for 3 years and ends on the 27th September 2019 so only 5 months left!
I asked the DWP REP what would happen regarding review as usually You have a review sometime between 6 months to a year before the end date, and there is only 5 months left!
DWP rep did not know!
I queried this with the panel but they were dismissive of My concerns
Does anyone know if when the official decision letter from the DWP comes are they still able to lengthen the award so to allow for the time for a review as normal.
Any help advice appreciated!

Hi Gordon.
There was never an award in place, This is the first time an award has been actually given.

So usually 3 year awards if given by the Assessor are then made 4 years with a review date anytime after the 3 years.

So what I am asking is when the dwp get the decision notice can they extend the award to 4 years and so set a review time from September when the 3 years is up.

This claim was started in September 2016 and only decided today.