We propose an additive model for balancing the impacts of actions on values, where factors intensify or attenuate impacts on values, and values are assigned degrees of relative importance (weights). The balancing model induces axiological rules, consisting in prohibitions or permissions that are justified according to the impacts of the prohibited or permitted action on the values at stake. We also propose eight different revision operators, which shift the balance - and thus induce different norms - by expanding or contracting either the set of factors or the set of values. We provide the construction and prove some success properties of those operators.