Every field entry, including non-calculated fields, causes a recalculation

I am creating a 2-page fillable form. The 2nd page has calculations on each line. All except Machine Cost are using the product (x) of two fields. For Machine Cost, I have the below in the Custom calculation script:

var nResult=0;
var nA = 0;
var nB = 0;

//Acquire inputs
var nA = Number(this.getField("ListPrice1").valueAsString);

var nB = Number(this.getField("Discount1").valueAsString);

//Test if discount is 0 and perform calculation

if (nB == 0){
nResult = nA;
} else {
nResult = nA - (nA * (nB/100));
}

//Assign Result to Field

event.value = nResult;

Every time I enter anything into any field on the form, it is forcing a recalculation. There is a lag/delay and it looks like a calculator icon.

How can I prevent this from happening?

I am using Adobe Acrobat Pro Version 2023.008.20458