As the XC40 is getting a bit long in the tooth now, I’d expect to see some of the options become available on lower spec trims to keep up interest. Volvo have done this in the past – and it looks like they’re doing it now on the XC40 Plus trim to an extent. Either that or the higher level trims will come on to the scheme.
A reasonable chance especially with, as you say, the XC40 getting on a bit now, but Volvo have always been very half-hearted about Motability, so I wouldn’t hold your breath!