I have been working with a 'home-made' calculator for some time now. I have found it quite useful but then I do not bake that many sorts of bread. For now, I am only into Pain au levain, Buttermilk Sourdough Bread. I have also tried the Sourdough Bagels. First try was not so good - problem with the mixing. I am looking forward to better results on my second try soon. I do not know whether this calculator is of any use for the more complex types of bread.
I find that I cannot upload the calculator here. If you are interested to take a look, you can find the last version [Rev. 8] at Mellow Bakers: