Another angle to this is that they are quite likely experiencing record numbers of extensions which doesn’t particularly help their business model. So as well as all the obvious reasons for doing it they’ll be hoping it might just tip those wavering on an extension decision into ordering a new car.
I think that lease extensions help them greatly. Over 2 years they receive over £6k in additional sacrificed benefits and the servicing, MOT and cost of tyres etc will be less than £1k in the vast majority of cases. The remaining £5k more than covers year 4 and 5 depreciation and they also save on the capital outlay of buying a new car. The £250 is a pacifier, given that they made £1k additional profit for every customer on the scheme in just one year so feel compelled to give 25% of that back to stave off criticism – and the tactic seems to have worked.