As a sequel to previous papers, we assess, in a more general form, the performance of real income per head / capita using generalized aggregate production function under optimal control conditions. The role of the population growth dynamics in all of this is carefully tracked, especially as it varies from primarily exponential to sturdily logistic. Analytical, qualitative and numerical simulation procedures are used to decode the population associated parameters that engender qualitative variations in the evolution of real income per head. Non-labour factors of production per effective labour are here used as the state vector, whereas the output variable is income per effective labour, whilst consumption and investments relative to the above production factors, per effective labour apiece, become the control vector. The quadratic cost functional consisting of the control and state vectors, time-discounted, turns the objective functional. Largely, real income per head rises much quicker and generates higher time-values provided the population growth mechanism is chiefly exponential in contrast to being largely logistic, given the technological process of research and development (R & D). Contrarily, under any other technology, real income per head rather rises much quicker and generates higher time-values so long as the underlying population growth mechanism is chiefly logistic, and remotely utterly exponential. Such outcomes exert consequences across board with regard to economic management in underdeveloped (where population growth is exponential) and developed (where population growth is firmly logistic) economies alike, as well as those in-between these two extremes.