The thinking behind the current behavior on the Mac is that letting the "unavailable" color win out helps you focus on the due soon actions that have started. That said, we have had folks request that the "due soon" style override the unavailable one; if you email the
support ninjas, they can attach you to that request. (Ones with more customer interest attached tend to get assigned higher priority.)
That said, you can set your "Due Soon" period to 3 days in Data preferences, and the Styles pane can be used to color that style to green instead of the default orange. Does that help?