I really like the idea that you had of embedding the equations in the sheet. I'd like to get away from using my spreadsheet except for recipe formulation and Bru'n Water.

Trust me, you will get that point sooner than you think. You will eventually reach a point where you no longer need the spreadsheet for recipe formulation.

There was a point where I calculated all of the metrics, but I rarely calculate IBUs and extraction efficiency percentages these days. I went back to using points per pound per gallon (PPG) and alpha-acid units (AAUs) per unit of time when formulating recipes. A lot of newer brewers scoff at the idea of using these metrics, but they can be just as effective as machine calculated extraction efficiency percentages and IBU values when it comes to formulating reproducible recipes, and they are much simpler to compute. In fact, one can quickly determine amount of grain per gallon needed to formulate a recipe using PPG. For example, I shoot for a mixed-grist extraction rate of 29 PPG when using domestic 2-row as the base malt in a recipe (I can achieve a higher extraction rate, but the quality of the wort suffers with my system). With that PPG value, I can quickly determine the amount of grain that I need to make 5.5-gallons of SNPA-style 1.053 wort.

pounds_of_grist_per_gallon = 53 / 29 = 1.83lbs

pounds_of_grist = 5.5 * 1.83 = ~10lbs

or simply

pounds_of_grist = 5.5 * 53 / 29 = ~10lbs