There is only 1 energy, no matter what type of Reiki or holistic therapy you do it all comes down to the focus of intent. Maybe without having your hands placed, your intent wasn't fully on healing but on the cough itself? Energy is intelligent so regardless where your hands are placed or if you have used the symbols etc they will automatically come on.
Have you ever walked into a sacred place or a hospital/care home? My hands instantly start channelling the energy. There is also times where people will randomly come stand next to me and start chatting. Again I feel them the healing instantly begin without placing my hands or using the symbols
Hope this helps