I just came across an article that perfectly describes the difference between a spending plan and a budget:
We are blessed that our program recognizes that a budget won’t work for compulsive debtors and spenders, who rebel against deprivation. While we live within our means in D.A., how we do that is where the art of creating a spending plan comes into play. This is why it is wonderful that we have the tool of a PRG (pressure relief group), where two other recovering members meet with us to help us develop and maintain our spending plan, which can change with life circumstances. This team also keeps us from going to extremes either way — by allocating too much to our wants or or debts — helping us live a balanced financial life.