The problem is that ExpandControl had:
.rc.AddSetObserver(.set_summary)
This will only call the observer when a new record is set i.e. when you go to a new record in the Access
If you change it to:
{
.rc.AddObserver(.set_summary)
.rc.AddSetObserver(.set_summary)
}
Then it will be called whenever a field changes, which is what you are looking for.