Indicate incoming resources on building info window

Right now, if there is a delivery of construction parts incoming to a building, then using unity is a waste. Adding some kind of indication that there is one or more deliveries en route would be quite helpful.
Something like this:
20 (+15) / 50
First is the materials already on site, the one in brackets are the stuff being delivered, and the last one is the goods required to finish.
Giving the en-route stuff a different color could help tell them apart (also could just add a small "this is what this means by the way" note on the window next to the numbers).