Simple form requiring simple Javascript, tearing hair out

Use this as custom calculation script in "Total" field, it will calculate all checkboxes and add 6.9% increase if withdrawal is checked:

var fields = [
  "MarketingPackageA",
  "MarketingPackageB",
  "MarketingPackageC",
  "Audience Maximiser",
  "Photo For Sale Sign",
  "Sunset Photoshoot",
  "Be Seen Social Media",
  "Auctioneer’s Fee",
  "Body Corporate Disclosure Statement",
  "Title Search"
];

var per = 1.069;
var total = 0;

for(var i=0; i<fields.length; i++){
 var f = this.getField(fields[i]).valueAsString;
 if(f !== "Off")
  total += Number(f);}

if(this.getField("Withdrawal").valueAsString !== "Off")
total = total*per;

event.value = total.toFixed(2);