Rob, I knew of the new name, it just has not stuck in my memory yet. When Chad used it, I accept it as standard. I just have a hard time remembering it. Jim - FBM are not a special case. They are prone it the same cross-talk. FBM is/are just the first of the ERC. The technique for all is the same. Rob and Charles discovered that the function behind FBM will work in many other ways. I understand your resistance - but once you experiment a bit I think you will be a convert. You just need to get the grease under your nails first. It is a bit daunting in the abstract. Just reading about it will turn your brain to mush. It is a hands-on = eureka! type thing - at least it was for me. Dan's program will help a lot. Now, if we could just put in conditions or allow equations in the DeltaAddDelta line....