If mutations are turned on it does make difference from evolutionary point of view.
When a bot reproduces, the children is often in some way mutated, usually for worse. The more energy the less fit offspring is given, the higher it's changes of survival and reproduction are and lower the changes of survival are for more fit parent, which could reproduce more healthy bots if it survived. So, if the less fit get's to reproduce and the more fit don't, the future generations get less fit.
On the other hand, if the descendant get's too little energy, their changes of survival are low, beneficial mutations or no, and they may not reproduce at all. Then the line could die, even if it contained extremely beneficial mutations that others do not have.
So the energy given to offspring has to balance between giving enough energy for the offspring (and the genome of the parent) to survive and giving little enough so that the fit ones can reproduce and as many as possible of the less fit ones don't.