Add a Total Row at the bottom with custom formulas

[creativFuture]

Hi I have the following project where I have sample marketing data.

Sample data

In the source sheet I have a row at the bottom that tallies up the columns. Some of the columns are sums as others are simple equations such as the Ad Spend Column divided by the Outbound Clicks Column. As "Total" is not a date, I get invalid date at the bottom of the column. If I set the date column to plain text the dates read as date numbers (i.e. 45303) instead. Id like to be able to generate these same formulas within a row in appsheet. I wish I could add a "virtual row." Also worth noting, its not worth it to export the data from google sheets into appsheet database, because these numbers update regularly, especially the ones in the current month, and so far I haven't seen appsheet database live update from source sheet.

The long and short of it all is can anyone please tell me how I can have a "totals" row at the bottom of the table? 

Thank you all very much for your time and help in advance!