Hello @David_R ,
Yes, this can be done. A lof has been written about this type functionality, including by myself. There are a couple of things you need to be aware of, but for a lot of tables it is workable.
I have made a (documented) example to show how it is done. For good measure I have added column shading. Make sure you copy the document and check the column formulas to see how it is done.
inside Coda a previousRow function is not yet available, though the Coda team knows this is one of the missing elements if it wants to replace spreadsheet logic even more.
I wrote an article about with some tricks to apply such a previousRow logic. You find it here: