I believe that if you are currently paying Total Allowance, that changes to the amount of the DLA/PIP in force at the end of the 3 year period, ie if DLA is £50 a week, that becomes your new payment, so, if DLA then increases, you would receive the difference in your bank.
As for the warranty, that is Motability’s problem, not yours and they would pick up the bill for any work needed, so you still have the same peace of mind
Previous Motability Cars
2006 - 2009 Skoda Superb VR6 2.0tdi
2009 - 2012 Citroen C5 2.0tdi VTR Nav
2012 - 2015 Nissan Qashqai 1.5dci tekna
2015 - 2018 Ford Kuga 2.0tdi Titanium X
2018 - 2021 BMW 220d X drive 2 Series Active Luxury
2021 - 2023 Hyundai Kona Electric Premium SE
2023 - Hyundai Kona Electric Ultimate