Insert Data as if a human is doing it


I am trying to achieve a certain behavior and not sure how to achieve this. I need to simulate manually altering a field in a table. Right now I have a table being generated and displayed. I have an additional field added in and populating as zero. You enter a value, it does a quick calculation and kicks off a trigger to run SQL to populate other tables.

Below is the three phases, the first is the table populated but the blend fields are at 0 (Zero), then phase 2 is you enter the amount you want to use in this case I did 300; 1000; 95 and then pressed save. That brings us to phase 3 which then populates to the tables on the right and that the balance field was updated.

I would like a way to be able to place a button just above the table that says Use All Volume which then takes the number in the Volume column and places that in the Blend Column and leaves me with the option to press Save?