I am looking at a superheat charging chart and there is one thing I don't understand. I know how to use the chart, I just want to understand the thermodynamics.

When the ambient condensor temperature is constant, the system superheat increases with increasing return air temperature. OK, that one's obvious.

Now going through the chart in the other direction, for a constant return air temperature, the superheat DECREASES with INCREASING ambient condensor temperature.
So, if a system is charged correctly, the superheat will be SMALLER at a higher ambient condensor temp (for the same return air temp)?
Can someone explain the physics behind this? I don't understand why that is the case.