You can get Net Production/Usage from the downloaded CSVs by simply adding Total Usage and Solar Production (Solar Production is negative in the CSV) for the same hour or day. Very easy to do using a Pivot Table, especially daily. Net Production is the negative of Net Usage.
If you want “From Grid” and “To Grid” you can get a good approximation but not 100% exact by exporting hourly CSV, computing the Net Usage, as above, on an hourly basis, then segregating the positive and negative Net Usages into separate ‘To Grid’ and ‘From Grid’ columns. Positive Net Usage goes into the ‘From Grid’ and negative Net Usage goes into the ‘To Grid’ column.
Not super hard, and much easier than adding by hand into a spreadsheet. I can share an Excel-based example in the next day or so if you are interested.