When recording in units, there are a few factors that could make your total product applied end up slightly different then the actual total product applied. For some of you, that small difference doesn't matter, for others, you want to be exact down to the last ounce. Either way you prefer, you can edit the total product applied.
Make sure you are recording in Units (instead of how many tanks or gallons, you'll just be recording how many acres you treated)
Select the product line you want to change, and all the way on the right there is a little box with a pencil.
Select that and update the amount used. Voila, all done!