Ott`s answers have always been so and so...some of them hint staying, others leaving. Yesterday for example, when asked about staying in M-Sport and title plans for 2018, he says that is the plan because they have a good car etc (10.50). In the beginning he also says that this year has been so successful because he developed the car to his needs.
Or he is referring to another competitive car, but because not being a native speaker....
https://www.youtube.com/watch?v=2HYGpef9x68
https://twitter.com/ericdobro/status/911626647971012608
He has also clarified his tweet a bit, but obviously in french.