An information handling system having plural processing modules, such as an information handling system blade chassis having plural information handling system blades, allocates power by determining an actual load sharing power loss associated with plural power supplies and applying the actual load sharing power loss to determine how much power to allocate to the information handling system modules. A chassis manager determines actual load sharing power loss by retrieving power information from plural power supplies. The actual load sharing power loss replaces a worst-case load sharing power loss assumed value to increase the amount power available for allocation to the information handling system modules.