The reason for the lower price is simple: the Mobility element (PIP/DWP) went up by 10% in April, hence the dealers can charge less for AP now.
It won’t be down to that, or we would have seen price deceases across the board, which we haven’t. APs can vary wildly and it’s due to the deals that manufacturers are prepared to do which depends on countless factors. As Mitch said, new cars to the scheme often launch with high APs and then settle down, but there is often no obvious logic!