The results are completely out of our hands. We never know the actual external effects of our actions. For example, when we help others we may, unknowingly, be creating more problems for that person. Those problems may not become evident until much later.
So, in reality we never know all the results of our actions and we can never control those results because reality is uncontrollable. If this the case then what do we know for sure? If we are mindful we can always know our intentions. In fact, intentions arise before any bodily or verbal actions. Therefore the precepts are there to work together with right intention. It is intention that allows or prevents us from following of the precepts.
The Buddha's teachings require a different way of looking at reality. If you continue your mindfulness practice according to our meditation booklet you will see this clearly soon.