Adobe Acrobat Pro DC/Dropdown List/Automatically texts in fields

Hi, I am trying a similar code. Issue:when I select productRow1, it overwrites description in ProductDescriptionRow2.

ProductRow1 should populate description in ProductDescriptionRow1 and CostRow1

ProductRow2 should populate description in ProductDescriptionRow2 and CostRow2

{var VarDescrip = { AB5645_Q25: {FullDescription: "6 Part Quantity 25", Cost: "6.00" }, AB5650: {FullDescription: "4 Part Quantity 50", Cost: "8.00"}
}};

function SetFieldValues(ProductRow1) {

// Populate fields with values from the Description Data Object
this.getField("ProductDescriptionRow1").value = VarDescrip[ProductRow1].FullDescription;
this.getField("CostRow1").value = VarDescrip[ProductRow1].Cost;
}

function SetFieldValues(ProductRow2) {

// Populate fields with values from the Description Data Object
this.getField("ProductDescriptionRow2").value = VarDescrip[ProductRow2].FullDescription;
this.getField("CostRow2").value = VarDescrip[ProductRow2].Cost;
}

All properties of the 2 dropdowns ProductRow1 and ProductRow2 and the corresponding Description and Cost fileds are the same.

Dropdown Custom Keystroke Script 

//SetFieldValues()
if( event.willCommit ) {
if(event.value == " ") this.resetForm(["ProductDescriptionRow1", "CostRow1"]); else SetFieldValues(event.value);
}

Commit selected value immediately - Checked

Thank you very much in advance.  

Apply the zip-code as the export value of each item in the drop-down field, and then use this code as the calculation script of the text field:

event.value = this.getField("Name of drop down field").valueAsString;