Calculating a data field based on another data field of the same thing

Hello all,
I am building a Golf Score App.

I am Making Changes to a data thing.
That thing has a field called GIR (for Greens-in-regulation).
I have another field called GIR Missed (Greens-in-regulation missed).

In one single Making Changes to a data thing workflow element, I had both fields updated.
However, the GIR Missed is calculated based on the GIR field.
Example: GIR Missed = Number of holes on golf course - GIR.

The GIR Missed did not update in my database.

What I have to do for this GIR Missed to be updated, is to have a second Making Changes to a data thing to update the same database thing as above, to calculate only the GIR Missed value.

My problem is that I have to make two calls, with Search for workflow, which is costly, bandwidth wise.

Any comments? Am I doing this right?

Guy

How is the GIR Missed field calculated?

GIR Missed = Number of holes on golf course - GIR

I am realizing that perhaps, when a golf score and putts is entered, all I need to store are those two data (score and putts).
The remainder of the fields for a Golf Round could be done in the background. I am just not sure how to create a background data processing.

And how is the GIR calculated?

GIR = Number of holes for which the ball is on green in certain number of shots. If the hole PAR - hole player score = 2 or less, then we have a GIR.

Surely you can calculate the GIR Missed by calculating the GIR, then just deducting that from the Number of holes on the golf courseā€¦? no?