The fundamental problem here is that we've had pretty well documented explanations on how junctions need to be mapped in order for DPM to have *any* chance of working, but we have no way of knowing whether an off-and-on route is subsequently given at a junction because the mapping is still wrong or simply because (as has been seen numerous times at numerous junctions all over the country, if not the world, over the years since DPM was introduced) DPM has stopped working for reasons.

So given that the change you claim "fixed" DPM last time isn't one that makes any sense given how we know DPM works, and given there's no way to prove whether making a similar change now would be the reason why DPM appears to have started working again if that's indeed what does occur, then you should be able to understand why we're all reluctant to make a change that appears wholly unnecessary.

Now true, we don't know with absolute certainty how DPM operates at the server level when routes are being selected/rejected, however if it didn't work as documented then we'd be seeing far bigger problems than this one all over the motorway network, at junctions where entry slip naming routinely includes the main carriageway segment name as a substring, and where the off and on route can often provide a far more significant time saving than here. But we're not seeing this. You've had responses here from several UK Champs with nationwide editing rights - if anything unusual was happening on the motorway network regarding DPM, we'd be the ones to notice it. We haven't, which suggests DPM is still behaving as expected and at a reliability level consistent with how it's performed throughout its existence.

This UR has now been added to an internal bugtracking thread the developers are using to investigate DPM problems, so no alterations should be made to the map data here, nor should the UR be closed, until they've had a chance to look into it themselves.