If solar panels block the sun from heating the roof in Summer (making it easier to cool) then the reverse is true in Winter. Some amount of free energy is no longer hitting the roof and potentially changing the energy equation.

Is it a meaningful difference, I am not sure. However, it is only fair to count the impact on both seasons. Heating costs are significantly higher than cooling (larger absolute temperate delta required to go from 30f to 70f than 90f to 70f)