I am having some trouble to complete de Water Reduction Calculator.

The Project is a whole building, being each floor a different dwelling unit. They are luxury homes, so they are pretty big. In the calculator you can only introduce 4 fixtures for each category. In this Project, we have more tan 4 different fixtures for each category. That is one of the issues. The other one is that we are only allowed to fill one row for each dwelling unit, that again, only let you introduce 4 fixtures. For example, if each unit has 6 differents showers, with different flow rate, which one is the right way to reflect the real water consumption?