Having just skimmed through the Motability Annual Report (posted in another thread) there are several mentions that Advance Payments will be rising, which continues the trend of the last few years. There will always be exceptions, but the overall trend is going to remain upwards.
And Motability will be factoring in the “new” EV road tax from April 2025.
See the “additional rate “(expensive car supplement for cars over £40,000)
https://www.gov.uk/guidance/vehicle-tax-for-electric-and-low-emissions-vehicles