At the moment, tables are just a place to store static information (either reagent lists/maps or result tables). There are a number of improvements that we have in mind for the future. We hope to be able to add support for formulas later, to have a flexible system that will allow simple calculations. I am not sure when I will be able to do that, though, and what level of sophistication we can achieve. Note that you can already in the current version use Numbers or Excel files very easily in an experiment or a protocol. The file is stored safely inside the document package, within your Findings library. It can be opened and modified as needed by double-clicking on the file icon.
Many thanks for your feedback!