There's a bug in turret cost in the following situation:
1. Have a lv 3 turret already at a planet
2. Queue up an Upgrade Turret action, followed by a Build Turret (not sure if that second part matters or not)
3. Enemy fleet comes in and destroys the lv 3 turret
4. The Upgrade Turret action turns into a Build Turret action (why? shouldn't it just disappear?), BUT it costs 160 (the upgrade cost of the lv 4).
The planet has 42 resources, but still says, "waiting for 118", when it should have already started building the turret long ago. You have to go into the queue and delete the Build Turret action that the game replaced, and add a new Build Turret action to get past this problem.