I would like to sum a quantity over a running 12 month period

[greenbeast]

I have a simple spreadsheet that i record my fuel usage on, the last column totals the fuel quantity over a running 12 month period. If uses SUMIFS in Google sheets, but this formula gets overwritten as blank when using my app.
I’m not sure how to write an expression to do this simple task in AppSheet.
Advice much appreciated