I have a form 'Stock' with 2 rows of data 'A' and 'B' for different quality of same stock. 

Another input form will have values that I want to add to both rows on submit. by add i mean if row A stock has a column with 10 and the input for that column is 10, then the new value will be 20 in the stock form.

I've got fetch working for one row A, but would like to know how to perform fetch and update for both on same submit?

Should I perform a second fetch?

Thx,

Rob