In the sim I had a g hyd loss + y overheat. It came up with vref + 25. (Which is worst case for slats only) As it was a stopping problem we agreed to turn on the y pump on base, and hopefully keep the pump for the brakes.
So we configured on downwind and got slats only as expected. (Flap 3)
We then turned on the y elec pump for the app. It worked for about a minute before it overheated again. In that time the flaps ran out.
On reviewing the status page the delta vref was now+ 10,(as we now had slats & flaps)
So if I understand your question yes the delta vref does update on the status page as things change, but no I can't give you a reference.