I am using the more generalized definition. Wikipedia says:
In 2003, Lovallo and Kahneman proposed an expanded definition as the tendency to underestimate the time, costs, and risks of future actions and at the same time overestimate the benefits of the same actions. According to this definition, the planning fallacy results in not only time overruns, but also cost overruns and benefit shortfalls
I am using the more generalized definition. Wikipedia says: